A46 Newark - Lincoln Improvement ONE YEAR AFTER STUDY

Transcription

A46 Newark - Lincoln Improvement
ONE YEAR AFTER STUDY
January 2005
A46 Newark - Lincoln
Improvement
ONE YEAR AFTER STUDY
January 2004
JOB NUMBER: 4416515.600
DOCUMENT REF:
A46NewarkLincolnOneYearAfter_V1.doc
V1
One Year After Study
HC
V2
Predicted & Actual Flows
NB
Originated
Revision
Purpose
Description
JM
PR
May 06
Checked
Reviewed
Authorised
Date
POST-OPENING PROJECT EVALUATION
A46 NEWARK-LINCOLN IMPROVEMENT - ONE YEAR AFTER STUDY
Contents
Section
Page
Executive Summary
ii
1
Introduction

Improve the reliability of journey times by dualling, which allows traffic to flow
smoothly and to overtake safely; and
1-2

Improve safety by separation of carriageways and removal of direct farm accesses1-2
2
3
4
5
6
1-1
Purpose of the Report
1-2
Data Collection and Evaluation
2-4
Data Collection
2-4
Summary of Observed Impacts
2-7
POPE Methodology
3-17
Introduction
3-17
Vehicle Hour Benefits
3-17
Changes in Link Transit Time
3-18
Changes In Accident Benefits
3-19
Summary of POPE Methodology
3-20
Economic Benefits
4-21
Introduction
4-21
COBA Re-evaluation
4-21
Comparison of POPE and COBA Methodology
4-25
Re-Evaluation of Scheme Costs
4-26
Evaluation Summary Table
5-28
Introduction
5-28
Appraisal Summary Table (AST)
5-28
Outturn Effects
5-31
Summary of Conclusions
6-40
Appendix A – Journey Times on the A46 Improvement
i
POPE _ A46 Newark - Lincoln OYA _ final
44
Executive Summary
The A46 Newark – Lincoln Improvement Scheme officially opened on the 10th of July 2003.
The scheme has an online dualling of 13km from a single carriageway road as well as
providing a 2.5km bypass of the village of Brough, improvements to existing roundabouts,
and construction of new roundabouts and junctions.
The main objectives of the scheme were to:

Improve the reliability of journey times through dualling in order to provide the ability
for overtaking; and

Improve safety, by the separation of carriageways and removal of direct farm
accesses.
‘Before’, ‘Just After’, and ‘One Year After’ traffic, travel time and accident data was collected
to monitor the effects of the new scheme following its opening. This report of the One Year
After Study presents the observed impacts of the scheme, one year after it has been opened
to traffic and details the assessment of the scheme performance against the economy and
safety appraisal objectives using the One Year After POPE methodology. The environment,
accessibility & severance and integration objectives were also briefly assessed and reported
here.
The main observed impacts are as follows:
 Daily traffic flows on the improved section rose in estimated Annual Average Daily
Traffic (AADT) terms by 1,870 vpd between 2002 and 2004 (taking into account the
seasonal variations), indicating that, beyond the background traffic Growth1
(responsible for 61% of the Growth), there has been rerouting of vehicles from
alternative routes to the A46 improvement, essentially along the northern section of
the improvement;
 There are Journey time savings of 4 to 6 minutes for vehicles travelling along the A46
improved section, consistent throughout the day, indicating that the improvement has
been successful in reducing Journey Times along the route, as well as improving
their reliability;
 Although accident statistics from One Year after do not allow new trends2, compared
with an average of the three years prior to the improvement on the A46 and the
surrounding roads, the results show an overall decrease from 63 to 52 accidents per
year.
The main outcomes of the POPE assessment to note are:
On the Economic & Safety Impacts
 While the link travel times have improved substantially above the predictions, junction
delays as well as operating costs have increased above the predictions due to the
1
A national average traffic Growth of 2% was used.
A minimum of three years data is required in order to obtain statically significant accident trends
given their random nature.
2
ii
higher traffic Growth than predicted, leading to an overall scheme economic benefits
slightly below the OPR predictions (3.2% less). Such sudden growth in traffic is not
sustainable in the future, which means that the scheme economic benefits should
improve in the future to the level of OPR predictions or above. The evidence for this
should come from the 5 Years After Study, where longer term trends are established.

The cost of the improvement was estimated to be £28.77m (at 1997 prices and
values), whereas the actual costs converted to the same price base suggested
£25.913m, showing the outturn is 10% below predicted.
 During the one year after opening, there were 11 accidents on the A46 improved
section, against an average of 22 accidents yearly during the three years prior to
scheme opening. The most common causes of accident prior to opening were
collisions at roundabouts, junctions, and other shunts, while after opening accidents
mostly involved single-vehicle accidents.
 When traffic volumes (AADT) are considered, the annual accident rate for the A46
Before was 0.212 Personal Injury Accidents per Million Vehicle Kilometres
(PIA/MVKM). The equivalent rate One Year After was 0.076, which is significantly
lower, as a result of both fewer accidents and despite the increase in traffic volumes
after opening.
On the Environmental Impacts
 The environmental impacts of the A46 scheme have not been evaluated in detail.
The main premise for the benefits identified in the AST is that a great number of the
properties in Brough village will experience an improvement in air quality and a
decrease in the levels of noise generated by traffic. As the traffic reduction in the
village and traffic levels on the bypass are in line with the forecasts it is fair to say
that the environmental impacts reported in the AST are likely to have been achieved.
 As for the forecast negative impacts on landscape, biodiversity and water, the One
Year After site visit surveyed the route and checked that the implementation of the
mitigation measures is progressing as claimed in the Environmental Statement.
On the Accessibility & Severance Impacts
 Accessibility in Brough village has substantially improved as a consequence of all
through traffic has transferred to the bypass which helped restoring Brough village
setting and improved the safety of pedestrians crossing the main village road used
solely by slow moving local traffic.
 Along the remainder of the improvement, severance has been mitigated by the
provision of roundabout junction at Thurby and grade separated junction at Thorpe,
both offering a full U-turning facilities.
On Integration
 The planned 400 homes and more than 70 hectares of employment land at RAF
Swinderby site are implemented.
 In Lincolnshire, In Lincolnshire, the dualling of the A46 between Lincoln and Newark
has helped stimulate the development of several "gateway" sites, especially in North
iii
Hykeham. Initially this development has been used like car showrooms and food and
drink outlets but more recently offices and other industrial uses are coming forward.
It is hoped that the longer-term benefits of this new infrastructure will spread to the
urban core of Lincoln where some key regeneration initiatives need to be
accelerated.

In Nottinghamshire, the improvement to the A46 assisted in improving movements
between Newark and commuter villages to the north such as Collingham, and wider
with those using services in Lincoln. The main employment sites in Newark lie astride
the northern end of the Town with good links to the A1, A17 and A46. Again, the A46
improvement improved business links to Lincoln and augmented the locational
advantages of the industrial areas.
iv
POST OPENING PROJECT EVALUATION
A46 NEWARK-LINCOLN IMPROVEMENT – ONE YEAR AFTER STUDY
1 Introduction
BACKGROUND
1.1
The A46 Newark-Lincoln improvement scheme was opened on the 10th of July 2003,
providing a dual carriageway section of the A46 between the junction with A1133 north
of Newark-On-Trent and the junction with A1434 south of Lincoln, and a by-pass of the
village of Brough. The scheme is expected to significantly improve road safety by
reducing the number of accidents, reducing congestion and driver frustration and
improving journey times by allowing traffic to flow smoothly and overtake safely. The
Brough Bypass will significantly enhance the environment for villagers who have
effectively had their community severed by the old A46, and the scheme as a whole is
expected to encourage regeneration of the area.
1.2
The location of the Scheme in relation to Newark and Lincoln is shown in Figure 1.1
below.
Figure 1.1 – Location of Scheme
1-1
1.3
In order to assess the immediate responses to the new scheme, ‘before’ and ‘after’
traffic volumes and travel times data on the A46, surrounding roads and alternative
routes were collected immediately prior to (June & July 2002) and after (July 2003) the
improvement. In addition, traffic data from surveys carried out on the County roads
from Nottinghamshire County Council and the Highways Agency temporary and
permanent sites was obtained to evaluate the immediate effects of the improvement
on traffic levels and travel times. The results of this were reported in the Traffic Impact
Study Report, issued in April 2004.
SCHEME OBJECTIVES
1.4
The scheme is expected to significantly improve road safety by reducing the number of
accidents on the A46 and alternative routes, reducing congestion and driver frustration
and improving journey times. The Brough Bypass will significantly enhance the
environment for villagers who have effectively had their community severed by the old
A46, and the scheme as a whole will encourage regeneration of the area.
1.5
The main scheme objectives were to:
 Improve the reliability of journey times by dualling, which allows traffic to flow
smoothly and to overtake safely; and
 Improve safety by separation of carriageways and removal of direct farm
accesses
1.6
The improved section is part of the A46 Leicester to Lincoln strategic route as a major
regional transport link between centres of population and employment in Lincoln,
Newark, and Leicester as well as a local road providing links between communities,
access to agricultural activities and facilitating public transport services.
PURPOSE OF THE REPORT
1.1
This report represents the ‘One-Year After’ impacts of the A46 Newark – Lincoln
improvement scheme. The report has been prepared as part of the Post Opening
Project Evaluation (POPE) Commission and builds on the Traffic Impact Study (TIS)
report prepared for the Highways Agency in April 2004.
1.2
This report will set out a number of assessments, namely:
3

A comparison of the ‘Before’ and ‘After’ traffic volumes on the A46 and other
roads in the corridor and illustration of how traffic volumes have changed
since the opening of the improvement;

A comparison of ‘Before’ and ‘After’ journey times on the A46 and routes;

An evaluation of predicted3 and outturn economic forecasts based on
changes in traffic volumes and journey times and other outturn effects in the
form of an Evaluation Summary Table (EST); and
e5
1-2

1.3
1.4
1.7
An outline of the accident levels on the route and its surrounding roads to
provide an initial indication on whether they have changed since the opening
scheme.
This report specifically considers the re-evaluation of the predicted benefits of the
A46 Newark – Lincoln improvement. The three main elements involved are:

To identify the costs and benefits originally forecast for the scheme at Order
Publication Report (OPR) stage;

To quantify the outturn (actual) costs and the outturn level of benefits actually
accruing, based on outturn traffic volumes and journey times data; and

To compare the results and quantify the difference in the Present Value of
Benefits (PVB).
In addition to this introduction, the report has been divided into five further sections
as follows:

Section 2 outlines existing data collation and new data collection and reports
on traffic volume and journey time changes attributable to the A46
improvement;

Section 3 presents an assessment of predicted and outturn economic benefits
using the POPE journey time methodology;

Section 4 presents the original economic results, calculated by the
Department for Transport’s program COBA for the scheme in 1998 and the
level of benefits that would have been forecast if outturn traffic volumes and
journey times were known at the time. The section also compares the COBA
and POPE methodology;

Section 5 presents the original Appraisal Summary Table (AST) and then reevaluates the predictions within an Evaluation Summary Table (EST). The
section also gives an early indication of changes in the number of accidents in
the corridor;

Section 6 summarises the main conclusions from the evaluations and the
limitations to use.
It should be noted, that the ‘One year After’ report is primarily focused on the
evaluation of the Economy and Safety Objectives of GOMMMS. For the Environmental
objective, although this will be evaluated in details and will form part of the ‘Five Years
After’ POPE report, we present here, in Section 5 an outline evaluation of the scheme
environmental impacts and an initial assessment of the success of mitigation
measures.
1-3
2 Data Collection and Evaluation
DATA COLLECTION
2.1
For the ‘One Year After’ assessment of the A46 improvement scheme, the following
data was collected:
‘Before’ Data
2.2
2.3
Traffic volumes from:

4 Nottinghamshire County Council Count Sites

2 Permanent HA Count Sites;

4 Temporary HA Count Sites.
Journey Times from surveys undertaken in June 2002 and July 2002, before
construction began, in order to ensure ‘normal’ operating conditions and avoid possible
delays caused by construction work.
‘After’ Data
2.4
For the ‘One Year After’ assessment, the following data was collected:
Automatic Traffic Counts Data from:




ATC data from Highways Agency Area 7 Monitoring Sites, from:

Site 2028/9: A46 near Thorpe, monitoring before and after the improvement;

Site 9721/2: A46, East of sewage works;

Site 9433/4: A46, WHISBY;

Site 9713/4: A1 Shirebridge, south of Newark; and

Site 9777/8: A1 Cromwell, north of Newark.
ATC data from Nottinghamshire County Council Sites, on:

A1133, South of Langford (North of Gainsborough Rd);

A617, west of Kelham;

B6166, Newark; and

C208, Beacon Hill Road, Newark.
ATC data from Lincolnshire County Council Sites, on:

A607, Harmston, south of Lincoln; and

A17, west of Leadenham.
Two weeks ATC data from Temporary Sites using Tubes installed by Paul Castle
Consultancy on behalf of Atkins, on:
 A46 new bypass at Brough;
2-4
 A46 old road at Brough;
 A17, east of Beckingham; and
 A1133 at Girton.
Manual Classified Turning Counts Data from:
2.5
Paul Castle Consultancy counts on behalf of Atkins on the:
 A46/ A1133 roundabout, northeast of Newark; and
 A46/ A1434 roundabout, southwest of Lincoln.
2.6
The locations of the automatic and manual counts from the above sources are shown
below in Figure 2.1.
Figure 2.1 – Locations of Count Sites
Journey Times Data
2.7
Journey time surveys were carried out by Paul Castle Consultancy on behalf of Atkins,
on the four routes surveyed ‘before’ opening and identified as ‘orange’, ‘blue’, ‘yellow’
2-5
and ‘red’. The four routes and the corresponding timing points are illustrated in Figure
2.2 below:

The red route along the A46 between the A1 and B1190;

The orange route along A1133 and A57 between the A46 north east of
Newark and the A46 north west of Lincoln;

The blue route along the A17 and A607 between the A46 and the A1434 in
Lincoln; and

The yellow route along the A1133 and B1190 between the A46 and the
A1434 in Lincoln.
Figure 2.2 – Journey Time Routes with Timing Points
Accident Records
2.8
Accident records from the three years before scheme opening and one year after
opening have been obtained from Lincolnshire and Nottinghamshire County Councils.
At the time of writing, Nottinghamshire have only been able to supply data up to 31st
May 2004, that is for 325 days after opening. In view of the small numbers involved, it
2-6
is not considered worthwhile to scale up the Nottinghamshire accidents to represent a
full year.
2.9
Records were obtained for the A46 improved sections as well as the main feeder
roads in order to contrast the effects of the scheme on the improved section with that
on the non improved feeder roads. This should assist in isolating effects directly
attributable to the scheme as a measure of the additionality of the improvement.
SUMMARY OF OBSERVED IMPACTS
Impacts on Traffic Volumes
2.10 Figure 2.3 overleaf illustrates the changes in daily traffic volumes on the A46 Newark –
Lincoln section and other roads in the area. All ‘Before’ and Immediately after (TIS)
traffic volumes have been factored up to reflect October 2004 traffic levels to ensure
the conclusions drawn take into account seasonality and normal traffic Growth.
2.11 The main points to note are:
4

The bypass has been effective in relieving Brough village from through traffic
and transferring it to the A46 dual carriage way. The village has recorded
around 98.5% reduction in traffic volumes from 26,0804 vehicles per day (vpd)
in 2002 before construction began down to just below 400 vpd (on an average
weekday), one year after the improvement. The de-trunked old A46 road
through the village is now carrying only local traffic and serving as an access
to/from the A46 new alignment.

A year after the improvement traffic volumes on the bypass amounted to
26,070 vpd on an average weekday. If the 400 vpd of local traffic in Brough
village is not taken into account as most of this likely to be generated from
suppressed demand, traffic on the A46 at the level of Brough indicate a yearly
Growth of 2%, in line with the national normal Growth levels.

Further north on the improved section, traffic volumes on the Highways
Agency permanent site near Thorpe recorded a Growth of 6.7% above the
normal Growth, responsible for 1,870 extra vehicles per day.
Adjusted to take into account seasonality and normal traffic Growth.
2-7
Figure 2.3 – Traffic Volume Changes around the A46 Newark – Lincoln area
2-8
2.12 The increases in traffic in the northern section of the A46 improvement are explained
by traffic changes elsewhere, namely:

On the A1133 route serving as alternative route between Newark and Lincoln,
north of the improvement, traffic volumes on Nottinghamshire County Council
permanent site, South of Langford have decreased by 700 vpd and on Atkins’
two weeks temporary site at Girton by 850 vpd.

On the A17-A607 route as southern alternative to A46 improvement, traffic
volumes on Atkins’ two weeks temporary site on the A17, east of Beckingham
have decreased by 3,100 vpd and on Lincolnshire County Council permanent
site, on the A607 Harmston south of Lincoln, have decreased by 600 vpd.
2.13 The above changes in traffic volumes suggest a rerouting of traffic from both the
northern and southern alternative routes to the A46 improved section. Taking into
account the stagnating traffic levels on Brough bypass, it would appear that the
rerouting is occurring along the northern section of the improvement (north of the
bypass) only. This could be the result of a combination of:

Traffic diverted to the scheme due to the improved access to the A46 from the
adjacent rural areas, encouraging rural traffic to take the A46 as their main
access to the road network instead of the A607 or the A1133, and

traffic generated from the new storage and delivery facilities recently built
along the northern section of the A46 improvement, south of Lincoln, attracted
to the area by the A46 improvement.
2.14 Growth in traffic on the A1 and the A617 is in line with the national average of 2%
yearly, suggesting that the more strategic long distance traffic using those roads is
indifferent to the improvement.
2.15 Traffic on the B6166 through Newark centre has decreased by 7.6% percent
suggesting rerouting of traffic to more usage of Newark bypass following the
improvement of the A46 route.
Impacts on Traffic Growth
2.16 As indicated above, once the effects of traffic rerouting and generation from new
developments are removed traffic Growth in the study has generally been in line with
the national average of approximately 2% yearly.
2.17 Given that the improvement was an online dualling through the construction of a new
southern carriageway, traffic throughout the construction period was not disturbed by
the construction works, and therefore had little or no effect on the route choice, timing
and frequency of trips, which explains the convergence of the traffic Growth with the
national average.
2.18 The following graph illustrates monthly variations of average weekly traffic over the
one year period following scheme opening on the Highways Agency’s permanent site
2-9
near Thorpe. Comparing the 2003 and 2004 figures for months October & November,
this shows a Growth of 8.5% in October and 6.0% in November.
A46 near Thorpe
35000
30000
25000
20000
AWT
15000
10000
5000
0
Oct2003
Nov2003
Dec2003
Jan2004
Feb2004
Mar2004
Apr2004
May2004
Jun2004
Jul2004
Aug2004
Sep2004
Oct2004
Nov2004
Month
Figure 2.4 – Monthly Variation in Traffic Flows on the A46 near Thorpe
Predicted and Actual Flows
2.19 The following table compares predicted and actual volumes for two links on the new
road: link 17 in the south, and link 34 in the north. The predictions have been taken
from the original COBA and factored from the year 2001 to 2004.These show actual
flows to be about 50% higher than predicted.
COBA
Link
17
34
AADT 2004
Predicted Actual
16,296
24,594
18,696
28,019
Table 2.1 – Predicted and Actual Flows
Impacts on Journey Times
2.20 The journey time survey was carried out on Thursday 14th of October 2004 during
unfavourable weather (fog) conditions. It was reported by the survey team that the
weather conditions have affected the visibility and driving conditions, resulting in lower
travel speeds and journey times that may not represent those of a normal day.
2-10
2.21 Following discussions with the Highways Agency it was agreed that it is unlikely that
the travel times on a normal day could be substantially different from those recorded
during the immediately after opening (TIS) journey times survey carried out in
September 2003, given that the traffic levels are much lower than the capacity of the
A46 dual carriageway. We would therefore, expect little benefit from repeating the
surveys.
2.22 Consequently, it was agreed to use data from the TIS journey times survey, after
validating them. The validation consisted of comparing traffic volumes and speeds on
the A46 and ensuring that they haven’t changed substantially. This was carried out by
comparing hourly traffic volumes and spot speeds in October 2003 and October 2004
months derived from the highways Agency’s classified site 2028/9 near Thorpe (West
of Thorpe Grange Farm, just south of the junction with A1434).
2.23 The comparison showed that the traffic flow and speed conditions were consistent
between 2003 and 2004, and it was therefore decided to use the TIS survey data for
the remaining of the One Year After POPE assessment.
2.24 We summarise below the main TIS journey time survey results:
2.25 A summary table of results from the journey time surveys for the four surveyed routes
is included in Appendix A for comparison between ‘before’ and ‘after’ results.
Direction
Period
AM Peak
Northbound Inter-Peak
PM Peak
AM Peak
Southbound Inter-Peak
PM Peak
A46 (Before)
A46 (After)
Time Saved After Scheme
Av. Time
17:36
17:15
17:43
17:46
19:06
17:17
Av. Time
13:32
12:41
13:14
13:29
12:23
12:39
04:04
04:34
04:28
04:16
06:43
04:38
Table 2.2 – Comparative ‘Before’ and ‘After’ Journey Tines
2.26 Table 2.2 above compares journey times on the new (September 2003) improved A46
Newark to Lincoln travel times (between A1 and B1190) and the old A46 (before
improvement in June 2002). This highlights that Journey Time savings of about 4.5
minutes (and up to 7 minutes) are shown in both directions and for all periods.
2.27 Appendix A also shows journey times on other routes in the area. The results show:

On the blue route, journey times have increased up to about 8 minutes. This is
largely due to road works along the A607 between Harmston and Waddington
and temporary signals at Harmston during the ‘after’ period;

On the orange route, journey times remain largely unchanged with an increase in
the AM peak, in the eastbound direction and an increase in the inter peak in the
westbound direction; and
2-11

On the yellow route, journey times have increased between 2 to over 5 minutes,
but at present no explanatory reason can be found for this.
Impacts on Journey Speeds
Direction
Period
AM Peak
Northbound Inter-Peak
PM Peak
AM Peak
Southbound Inter-Peak
PM Peak
A46 (Before)
A46 (After)
Speed Difference (KPH)
61
63
61
61
57
62
80
85
82
80
87
85
18
23
21
19
31
23
Table 2.3 – Comparative ‘Before’ and ‘After’
2.28 Table 2.3 above compares journey speeds on the A46 between the A1 and the B1190
‘before’ and ‘after’ the A46 Newark Lincoln Improvement Scheme, and shows that:

Typical journey speeds have increased from around 60kph to over 80kph; and

Journey speeds are also consistent for all time periods after the opening of the
A46 Newark to Lincoln Improvement Scheme, showing that journey time
reliability will be sustained in the future.
Impacts on Number of Accidents
2.29 The locations of accidents before and after scheme opening are shown in Figures 2.5
and 2.6 below.
2-12
Figure 2.5 – Accidents Three Years Before Scheme Opening
Figure 2.6 – Accidents One Year After Scheme Opening
2.30 For comparison purpose Figure 2.7 below compares le location of accidents three
years prior to opening with those from the On Year After
2-13
Figure 2.7 – Accidents One Year After Scheme Opening
2.31 In the three years prior to scheme opening, 66 accidents occurred on the A46 between
the A1133 and A1434. Examination of the causes indicates a breakdown as shown in
the following table. The most significant categories were collisions at roundabouts,
junctions, and other shunts, while overtaking and head-on collisions were relatively
rare.
Cause
Collisions at roundabouts
Collisions at other junctions including shunts
Other shunts
Overtaking & head-on collisions
Accidents involving tracors
Single-vehicle accidents
Other
Total
Number
12
17
15
7
1
9
5
66
Percent
18%
26%
23%
11%
2%
14%
8%
100%
Table 2.4 – Accident Causes on A46, Three Years Before.
2.32 During the one year after opening, there were 11 accidents on the same section of the
A46. Using the same categories, the causes are as shown below. It is seen that singlevehicle accidents were most numerous; however four of the six accidents placed in
this category also took place at roundabouts, so arguably accidents at roundabouts
could be the most important category.
2-14
Cause
Collisions at roundabouts
Collisions at other junctions including shunts
Other shunts
Overtaking & head-on collisions
Accidents involving tracors
Single-vehicle accidents
Other
Total
Number
3
Percent
27%
1
1
9%
9%
6
55%
11
100%
Table 2.5 – Accident Causes on A46, One Year After
2.33 Table 2.6 compares the A46 in the improvement section with links feeding it at either
end, in the three years Before. In terms of accidents per unit length, the rural A46 is
seen to have been safer than the extensions NE and SW, which are urban. A further
measure for comparison is “KSI Severity” which is the ratio of Fatal + Serious to Total.
Interestingly, this was highest on the A1 south of A46, a fast dual carriageway, where
the majority of accidents were Serious.
All
Accidents
Length
(km)
Accs per km
A46 improvement section
66
A1, S of A46, Newark
Section
Severity
KSI Severity
per Year
Fatal
Serious
Slight
13.04
1.7
1
8
55
0.136
9
2.00
1.5
0
7
2
0.778
A46 & B6166, W of A1, Newark
62
3.79
5.5
1
6
31
0.113
A46, N of A1434, Lincoln
10
3.64
0.9
0
2
10
0.200
A1434, E of A46, Lincoln
43
4.34
3.3
2
3
38
0.116
Table 2.6 – Accidents on A46 and Surrounding Links, Three Years Before.
2.34 A comparable table for the year after is given below. This suggests that the A46 and
surrounding links are now safer, although with only a single years’ data, the results
should be considered tentative.
Section
A46 improvement section
All
Accidents
Length
(km)
Accs per km
per Year
Fatal
Serious
Slight
11
13.04
0.3
0
1
10
Severity
KSI Severity
0.091
A1, S of A46, Newark
2
2.00
0.3
0
0
2
0.000
A46 & B6166, W of A1, Newark
21
3.79
1.8
0
3
18
0.143
A46, N of A1434, Lincoln
10
3.64
0.9
1
2
7
0.300
A1434, E of A46, Lincoln
8
4.34
0.6
0
2
6
0.250
Table 2.7 - Accidents on A46 and Surrounding Links, One Year After
2.35 When traffic volumes (AADT) are considered, the annual accident rate for the A46
Before was 0.212 Personal Injury Accidents per Million Vehicle Kilometres
(PIA/MVKM). The equivalent rate One Year After was 0.076, which is significantly
2-15
lower. This is the result of both fewer accidents and an increase in traffic volume after
opening. The comparison is shown in the table below, together with national average
rates for the same road types.
Road Type
AADT
(2-way)
pia/mvkm
Nat. Av.
pia/mvkm
13.04
Older S2 A-road
21,800
0.212
0.238
13.04
Modern D2 with HS
30,604
0.076
0.100
Accidents
per Year
Length
(km)
A46 before improvement
22
A46 after improvement
11
Section
Table 2.8 – Before and After Accident Rates on A46
2-16
3 POPE Methodology
INTRODUCTION
3.1
As part of this ‘One-Year’ After Study, the Report also assesses the predicted level of
economic benefits. This section compares these predictions with actual benefits
accrued in the light of actual traffic volume changes and actual journey time benefits.
3.2
The approach taken is termed the Post Opening Project Evaluation (POPE)
methodology. The basis of the POPE methodology is that through previous COBA
evaluations undertaken it has been identified that the majority of benefits are derived
primarily from two areas:
3.3

Link Transit time (vehicle hours) benefits; and

Accident Benefits.
As such, link transit time, (which is represented by traffic volumes multiplied by journey
times) and the number of accidents can be collected before and after scheme opening
and the difference between these observed values can be compared with the
difference shown in time and accidents for the same links shown in the OPR COBA’s.
The premise of the POPE methodology is that the change in the observed flows, times
and accidents can be directly linked to the economic benefits predicted for this
scheme. The following section outlines this approach in more detail.
VEHICLE HOUR BENEFITS
3.4
3.5
To calculate link transit time or vehicle hour benefits, the COBA input file from OPR
must be available, and the following changes implemented so that sensible and likefor-like comparisons can be made:

OPR - Do Minimum: Although flow and delay data was probably collected
prior to scheme implementation at the OPR stage, journey time and delay
information must be determined by re-running the COBA deck with a journey
time year set to the same as that when the Post Opening surveys were
undertaken;

OPR - Do Something: As with the OPR Do Minimum this data will need to be
determined from re-running the COBA deck for the survey year after opening;

Actual - Do Minimum: Pre opening count and Journey Time data is collected
for each new scheme route before opening. This information is obtained for
the AM, IP and PM time periods; and

Actual - Do Something: Traffic volumes and journey times from surveys
after the opening of the schemes are directly applicable to this scenario.
In considering the changes between the OPR COBA and the observed vehicle hour
benefits, we are limited by the availability of data. Only peak hour and off peak hour
journey times are available for the key links before and after opening, even though
count data has been collated for the whole 24 hour period. This means that only a
selection of links (where data IS available) is considered in the POPE assessment,
3-17
and thus the change in vehicle hours can be compared with the change in link transit
time for the same links in the OPR COBA.
3.6
The test assumes that flow data, on key links, is available by hour for a 24 hour period
and journey time data is only available for the peak and off peaks. This means that
expansion factors from peak hour to peak period and off peak period to all other hours
have been calculated from the Do Minimum observed flow data. This has then been
used to factor up the outturn data to a total average day.
CHANGES IN LINK TRANSIT TIME
3.7
Table 3.1 below shows the differences between the vehicle hours (observed traffic
volumes multiplied by times) before and after opening of the A46 Newark – Lincoln
improvement and the same difference for the same links as predicted during the OPR
COBA assessment.
Total Vehicle-Hours in 2004
Low
Growth
DM
740,951
OPR COBA
DS
713,305
Difference
27,646
‘Before'
920,036
Observed
‘After'
888,208
Difference
31,827
High
Growth
810,542
768,470
42,073
920,036
888,208
31,827
Table 3.1 - Comparison of Vehicle hours on the A46 Newark – Lincoln and the
bypassed Brough village road
3.8
Table 3.1 shows an outturn yearly saving in the observed vehicle hours of 31,850. For
the same links and scheme year, the Low Growth predicted a saving of 27,650.
3.9
It should be noted that the OPR COBA did not estimate the High Growth scenario.
This was rather estimated by Atkins for the sake of comparison by rerunning OPR
COBA with the High Growth option.
3.10 The OPR COBA assessment showed that the Link Transit Time benefits for this
scheme were £ 38.6 million. This means that the 27,650 vehicle hours saving
correlates to £ 38.6 million of benefits, and using the same relationship between
vehicle hours saved and economic benefits, the observed 31,850 hours saved
correlates to £ 44.4 million benefits. Thus, the outturn benefits are estimated to be
15% higher than what was predicted in the Low Growth scenario.
3.11 Table 3.2 overleaf summarises the POPE estimate of benefits for both Low and High
Growth for the Improvement schemes, and shows:

Low Growth - outturn benefits are estimated to be £44.4m, which are 15%
higher than those predicted;
3-18

High Growth – As stated above the original OPR forecasts were carried out
for the Low Growth only. For comparison purposes we estimated what the
OPR would have predicted for the high Growth by rerunning OPR COBA with
the high Growth assumptions. This gives a high scheme time benefits of
£72.1m for a saving of 42,050 vehicle hours. Outturn benefits for the high
Growth were then estimated using the same above approach used for the
Low Growth, gave a scheme outturn time benefits of £54.5m under the high
Growth assumption, thus % 32 lower than the “hypothetical” OPR High
Growth forecasts.
Difference in Vehicle Hours for A46 Improvement
OPR stage
Actual
Link Transit
Predicted
Difference
Difference
Time Benefits
Benefit
Low Growth
27,646
£38.6m
31,827
£44.4m
High Growth
42,073
£72.1m
31,827
£54.54m
Table 3.2 – Link Transit Time benefits for A46 improvement
CHANGES IN ACCIDENT BENEFITS
3.12 Table 3.4 below shows the difference between the actual number of accidents before
and after opening of the A46 improvement and the difference between the numbers of
accidents predicted by COBA.
Total Number of accidents per year
Low
High
Growth
Growth
DM
1175
1406
OPR COBA
DS
773
925
Saving
402
481
(reduction)
(34%)
(34%)
‘Before’
786
817
Actual
‘After’
393
408
Saving
393
408
(reduction)
(50%)
(50%)
Table 3.4 – Comparison of actual and predicted number of accidents on the A46
improvement and the surrounding area
3.13 COBA has predicted a saving of 402 accidents, for low Growth, whereas the actual
saving, along the same links and scheme year, is 393 accidents.
3.14 The OPR COBA assessment showed that the Accident Benefits were £18.671million,
at low Growth. This means that 402 accidents saved correlates to £18.7 million of
benefits, and using the same relationship between accidents saved and economic
3-19
benefit, the observed saving of 393 accidents equates to £18.25 million benefits.
Thus, the outturn benefits are estimated to be only 97.7% of what was predicted.
3.15 We also estimated OPR COBA Accident Benefits for the high Growth assumption. This
gives a saving of £25.75m. Under the same Growth assumption, the Outturn Accident
Benefits are estimated at £21.85m, or 84.8% of the OPR COBA forecasts.
Accident saving on the A46 improvement
OPR stage
Actual
Accident
Predicted
Difference
Difference
Benefit
Benefit
Low Growth
402
£18.67m
393
£18.25m
High Growth
481
£ 25.75m
408
£21.84m
Table 3.5 – Accident Benefits on A46 improvement
3.16 Table 3.5 above summarises the POPE estimate of accident saving benefits for both
Low and High Growth for the A46 improvement schemes, and shows:

Low Growth - outturn benefits are estimated to be £18.25m, which are 2.3%
lower than those predicted;

High Growth – outturn benefits are estimated to be £21.84m, which are 15.2%
lower than those predicted;
SUMMARY OF POPE METHODOLOGY
3.17 These results suggest that the POPE methodology may be a robust way of evaluating
link transit time benefits, particularly when most of the key links have all been counted
and journey times have been undertaken.
3.18 The POPE methodology for accidents should be treated with caution, as it is normal
for changes in accidents to be assessed over 3-5 years. Therefore, conclusions can
only be considered as indicative when they are derived from only One Year’s data.
3.19 Thus, the POPE methodology will continue to be used on other schemes in order to
provide a larger sample to verify POPE as an evaluation tool.
3-20
4 Economic Benefits
INTRODUCTION
4.1
4.2
Economic benefits of a scheme have been traditionally assessed using the
Government’s COBA (Cost Benefit Analysis) program, which considers changes in:

Link transit time, which is the time on each affected link both before and after
opening weighted by vehicle flows;

Vehicle operating costs (VOC), reflecting fuel and other operating costs
calculated by a change in total distance travelled on the affected links, but
also considering vehicle speeds; and

Accident rates and costs, which change after infrastructure improvements are
made as accidents are normally less frequent on new roads.
This section presents a comparison of predicted benefits as calculated by COBA and
an assessment of what those benefits would be if the outturn traffic volumes and
journey time savings were known at the time.
COBA RE-EVALUATION
4.3
4.4
The original Order Publication Report (OPR) COBA appraisal provided the level of
benefits that were predicted for these schemes at Public Inquiry. These COBA
assessments have been obtained from Government records, and then three additional
assessments have been undertaken to provide a re-evaluation of scheme benefits.
These were:

Replication of the original OPR COBA results, using the original COBA
version 10 (first release);

Re-assessment of benefits after the introduction of actual traffic volumes,
whereby the outturn figures are also input into the Do Minimum scenario; and

A validation of journey time definitions within the COBA to more closely reflect
actual journey times.
Figure 4.1 & 4.2 overleaf show the “stick” COBA networks used in the appraisal of the
Do-Minimum and Do-Something scenarios respectively and Tables 4.1 & 4.2 show
COBA results for the A46 improvement scheme for the Low and High traffic Growths.
4-21
Figure 4.1 – “Do minimum” COBA network for A46
Figure 4.2 – “Do something” COBA network for A46
4-22
A46 Newark-Lincoln improvement
LOW GROWTH
COBA Replication
COBA ITEM
OPR (printout)
Replication
38,599
38,599
Link Transit Time
-1,603
-1,603
Operating Costs
-2,555
-2,555
Junction Delay
17,136
17,136
Accidents
0
0
Construction Delay
-293
-293
Main Exp Saving
51,285
51,285
PVB (£)
Outturn Count
data included
47,736
-8,247
-7,495
17,936
0
-293
49,638
Table 4.1 - Present Value of Benefits for A46 at Low Growth (£ 000s, 1994
values, discounted to year 1994)
A46 Newark-Lincoln improvement
HIGH GROWTH
COBA Replication
COBA ITEM
OPR (printout)
Replication
72,136
Link Transit Time
-1,214
Operating Costs
-2,786
Junction Delay
Was not
25,752
Accidents
undertaken at
0
Construction Delay
the OPR stage
-293
Main Exp Saving
93,595
PVB (£)
Outturn Count
data included
71,229
-10,519
-12,248
23,858
0
-293
72,026
Table 4.2 - Present Value of Benefits for A46 at High Growth (£ 000s, 1994
values, discounted to year 1994)
4.5
Tables 4.1 and 4.2 show the re-assessment of economic benefits for the A46
improvement, where all costs and benefits are shown in 1994 prices in multiples of
thousands pounds discounted to year 1994 (at 6%). These show that the predicted
economic benefits of this scheme at the time of the Public Inquiry were estimated to be
£51,2855 m for a Low Growth assumption and would have been £93,595 m for High
Growth. We have replicated this assessment, as shown in the tables’ second column.
When the actual traffic volumes are inserted into the assessment, the benefits are
reduced to around £49,638 m for Low Growth (a 3.2 % decrease) and £72,026 m for
High Growth, which represents 23 % decrease. The Outturn column (ultimate column)
reflects the COBA run that would have been predicted had the actual 2004 flows been
known to the OPR consultant at the time.
4.6
As the tables show, despite the higher Outturn link transit time saving compared to the
OPR forecasts, the overall Outturn Present Value Benefits is lower due to higher
operating costs and junction delays than originally predicted.
5
The Present Value Benefits as it appears in the AST amounts to £55.3m. The difference is due to the
amendment of the user costs following the inclusion of maintenance delay savings which were manually
estimated and added to the total benefits.
4-23
4.7
As COBA version 10 does not provide the option of introducing the travel times
explicitly, but rather estimates them using links speed-flow curves, we therefore
compared the COBA travel time outputs with the observed travel times from the survey
carried out in October 2004 (or September 2003 to be precise). The comparison
shows that the difference is insignificant, suggesting a robust calculation of travel times
by COBA, mostly because of the free traffic flow conditions prevailing since the A46
dualling.
4.8
Table 4.3 below shows the COBA and Outturn results for the Low Growth. This shows
that the outturn benefits are 3.2% lower than predicted.
Predicted
Benefits
£m
Outturn
Benefits
£m
% Increase
£m
£51.28m
£49,64 m
-3.2%
Table 4.3 - Comparison of Economic Benefits for Low Growth
4.9
The previous section showed that additional traffic volumes have been attracted into
the A46 corridor from other routes, notably the A1133, A17 and A607. The COBA
network used for the assessment of benefits did not include these other routes and
therefore the predictions were based on a straight switch of traffic from the old road to
the new road. This approach clearly underestimated the level of benefits predicted for
the scheme. A larger COBA network that includes all links that experienced significant
change in traffic volumes and times would provide better estimate of the scheme
forecasts.
Accidents along the Improvement Scheme
4.10 Tables 4.1 and 4.2 show that the total predicted accident benefits of the A46
Improvement scheme was estimated to be £17.14 m for Low Growth. The inclusion of
outturn traffic volumes increases the level of accident benefits to £17.94 m in line with
the increase in link transit benefits.
4.11 COBA predictions do not therefore confirm observed accident savings, which show an
outturn saving lower that predicted. This however, is due to the unreliability of One
Year After observed accident data, and conclusions on the robustness of the POPE
approach should be saved to the 5 Years After assessment.
4.12 Table 4.4 overleaf shows that the outturn accident benefits are 4.7 % higher than
predicted under the Low Growth assumptions.
4-24
Improvement Scheme
Predicted
Benefits
£m
Outturn
Benefits
£m
% Increase
£m
£17.14m
£17.94m
4.7%
Table 4.4 - Weighted A46 Scheme Accident Benefits
COMPARISON OF POPE AND COBA METHODOLOGY
4.13 The previous section showed that actual savings in vehicles hours could be used as a
proxy for the change in link transit and accident benefits, whereas this section has
undertaken a good deal of COBA manipulation to insert actual traffic volumes into the
original OPR COBA, to evaluate the level of benefits that would accrue given the
COBA methodology, but using actual flows.
4.14 Tables 4.5 below shows the comparison, for link transit benefits for Low Growth,
between the POPE and COBA methodologies for the A46 improvement scheme,
followed by Table 4.6 showing the same comparison for the same Growth assumption
(Low) for the scheme accident benefits.
Predicted
Link Transit
Benefits
£m
Outturn
Link Transit
Benefits
£m
% Increase
£m
POPE Methodology
38.6
44.4
15.3%
COBA Methodology
38.6
47.7
23.6%
Table 4.5 - Comparison of POPE and COBA Methodologies for
Link Transit Benefits
OPR
Predicted
Benefits
£m
Outturn
Accident
Benefits
£m
% increase
£m
POPE Methodology
18.67
18.25
-2.2%
COBA Methodology
17.14
17.94
4.7%
Table 4.6 - Comparison of POPE and COBA Methodologies for
the Accidents Saving Benefits
4-25
4.15 This comparison shows that the POPE and COBA methodologies produce similar
levels of outturn link transit benefits, and thus POPE is potentially a robust way of
establishing outturn economic benefits without recourse to time-consuming COBA
manipulations. This is not the case when evaluating accident benefits. Clearly, the
two methodologies show very different results, at least in terms change between pre
and post scheme implementation. While POPE predicted a worsening situation, COBA
predicts an overall improvement over the whole scheme life. Other than the reliability
of the One Year After accident data, COBA assessment is based on project life
forecasts of accident saving whereas POPE assessment is based on observations
from One Year after opening only and therefore, the difference between the two
methods could be a result of an initial deterioration in safety as a result of a singular
traffic Growth immediately after opening and future accident saving trends will
converge with COBA predictions. This in a way confirms the general opinion that a
thorough accident assessment will require observations over longer period to allow for
effects of initial transitory fluctuations to fade away and for the longer term trends to
establish.
RE-EVALUATION OF SCHEME COSTS
4.16 As well as re-assessing the level of benefits accrued by the A46 improvement scheme,
we have also undertaken a review of predicted and actual costs. Tables 4.7 and 4.8
below present the predicted costs calculated before opening as part of the justification
of the scheme, as well as the actual costs converted to the same price base so that
direct comparisons can be made between them.
Construction
Land
Preparation &
Supervision
Total
predicted
£m
(1997 prices)
24.27
1.67
outturn
£m
(1997 prices)
22.72
1.60
2.83
28.770
1.59
25.913
Table 4.7 - Scheme costs based on 1997 prices and values
Construction
Land
Preparation &
Supervision
Total
predicted
£m
(2004 prices)
39.93
2.59
outturn
£m
(2004 prices)
36.86
2.57
4.39
46.911
2.56
41.989
Table 4.8 - Costs based on 2004 Prices and Values
4-26
4.17 The comparison of OPR and Outturn costs show:

£25.913m, showing the outturn is 10% below predicted;

Converting the predicted costs into current prices (2004) and values results in a
prediction of £46.911m against outturn costs of £41.989m.
4.18 Outturn scheme Preparation and Supervision costs incurred prior to 2001/2 were not
available at the time of writing and were therefore estimated at 7% (2% + 5%
respectively) of the scheme construction and land costs.
4-27
5 Evaluation Summary Table
INTRODUCTION
5.1
In order to evaluate fully the effects of the opening of the scheme, a review of the
Appraisal Summary Table (AST) has been undertaken. Table 5.1 presents the AST for
the A46 improvement.
5.2
The AST summarises the predicted impacts of the scheme across a range of different
sub-objectives. The sub-objectives considered within an AST are:

Environmental impacts such as Noise, Local Air Quality, Landscape,
Biodiversity, Heritage and Water;

Safety impacts, measuring reduction in accidents;

Economy impacts including savings in Journey time and Vehicle Operating
Costs, Scheme Cost and Reliability of journeys;

Accessibility impacts, such as change in access to public transport,
severance within communities and impact on pedestrian and other modes;
and

Integration, measured by how the scheme accords with local policy.
APPRAISAL SUMMARY TABLE (AST)
5.3
The main points to note from the A46 Lincoln-Newark improvement AST are:
Environment:

Bypassing the village of Brough would result in a decrease in noise levels for
17 properties, but an increase for 3 properties;

Bypassing the village of Brough would result in improved air quality for 24
properties, but a deterioration for 8 properties;

Biodiversity would experience a moderate negative impact by direct land-take
and hydrological effects on four sites of local conservation importance,
together with loss of ancient woodland and hedgerows;

Water would experience a moderate negative impact by pollution of
moderately sensitive watercourses during construction and operation, and
there would be an impact on flood risk as the scheme bridges several rivers;
and

No significant impact on landscape or heritage.
Safety

402 accidents, including 21 deaths, were predicted to be saved over 30
years;
5-28
Economy

Journey time reductions would be 4.9 minutes at peak times and 1.9 minutes
inter-peak;

Route stress would decline from 90% to 29%; and

Lincolnshire Objective 5b area would be served.
Accessibility

Slight positive effects in respect of severance and pedestrians crossing.
Integration

Lincolnshire and Nottinghamshire structure plans both highlighted the need
for improvements to the A46, to promote economic Growth, including the
development of the RAF Swinderby site.
5-29
Version of 03/08/98
A46 Newark - Lincoln (GO-EM)
Option: 1996 Scheme - 12.9 km on-line D2 widening of existing A46 + bypass
Cost £28.8m
PROBLEMS
Journey time reliabilty and safety problems caused by single carriageway road with farm accesses and slow-moving traffic combined with 19,000 vpd
(19% HGV). Some environmental problems where A46 passes through village of Brough (pop: 150)
OTHER OPTIONS
Parallel railway line, but development unlikely to remove sufficient traffic to solve problem.
CRITERIA
ENVIRONMENTAL
IMPACT
SUB-CRITERIA
Noise
QUALITATIVE IMPACTS
Benefits due to removal of through traffic from Brough. Without the
scheme 1 property would experience a significant increase in noise.
CO2
tonnes added
0-2000
Local air quality
Few properties adjacent to route - improvements largely due to
bypass of Brough.
Landscape
Biodiversity
No significant impact
Four sites of local conservation importance may beadversely
affected by direct landtake and hydrological effects. Some direct loss
of ancient woodland and hedgerows.
No significant impacts. Minor archaeological impacts, but balanced
by interpretative opportunities.
Even with mitigation, there may be: a significant risk of polluting
moderately sensitive watercourses during both construction and
operation;and an impact on flood risk as the scheme bridges several rivers.
Benefits due to separation of carriageways and removal of direct farm
accesses.
Journey times savings due to dualling providing opportunity to overtake.
Heritage
Water
SAFETY
ECONOMY
ACCESSIBILITY
INTEGRATION
Journey times &
VOCs
Cost
Reliability
-
Regeneration
Serves Lincolnshire Objective 5b area
Public transport
Severance
Pedestrians and
others
-
Largely on-line improvement except for bypass of Brough
Crossing A46 would be easier with scheme.
QUANTITATIVE MEASURE
No. properties experiencing:
- Increase in noise
3
- Decrease in noise
17
No. properties experiencing:
- improved air quality
24
- worse air quality
8
-
-
Moderate -ve
PVB £55.3m PVC £21.0m NPV £34.3m BCR 2.6
5-30
Neutral
Moderate -ve
Neutral
-
Table 5.1 – Appraisal Summary Table
-15 PM10
-58 NO2
-
Accidents Deaths Serious Slight
402
21
188
502
peak
interpeak
4.9 mins
1.9 mins
Route stress
before 90% after 29%
Serves regeneration priority area?
Development depends on scheme?
-
400 homes and >70ha employment land at RAF Swinderbysite likely
to be dependent on scheme. Lincs CC and Notts CC structure plans
highlight need to improve A46 access and economic growth.
COBA
ASSESSMENT
Net 15* properties win with scheme
PBV £18.7m
89% of PVC
PVB £36.6m
174% of PVC
PVC £21.0m
Slight
Low rel to PVC
Yes
Neutral
Slight +ve
Slight +ve
Positive
OUTTURN EFFECTS
5.4
In order to assess the Actual or Outturn effects of the improvement scheme, an
Evaluation Summary Table (EST) has been compiled, which mirrors the AST, and
includes details of the actual sub-objectives that have been evaluated.
5.5
The POPE process concentrates on economy and safety impacts of new scheme at
present, but this may be widened to include environmental effects, and guidance is
currently being fine tuned to outline the best approach for these objectives at present.
5.6
The main points to note on the EST are:
Environment
5.7
The environmental aspects of the A46 scheme have not been evaluated in detail. The
main premise for the benefits identified in the AST is that a great number of the
properties in Brough village will experience an improvement in air quality and a
decrease in the levels of noise generated by traffic. As the traffic reduction in the village
and traffic levels on the bypass are in line with the forecasts it is fair to say that the
environmental impacts reported in the AST are likely to have been achieved.
5.8
During the One Year After evaluation no assessment have been made on the noise and
air quality around the affected properties. However, to our knowledge no complaints
have been made by the residents or environmental statutory bodies.
5.9
As for the forecast negative impacts on landscape, biodiversity and water, the
Environmental Statement report (August 1992) suggested a number of mitigation
measures. During the One Year After site visit, the route was surveyed and the
implementation of the mitigation measures was visually checked. The results of the
survey are summarised in table 5.2 overleaf.
5-31
Mitigation
measure
Proposed
Outturn
Trees
plantation
Retention
of
mature trees along
the
road
and
replantation
of
native species to
restore ecological
and
landscape
balance.
Substantial amount of
old
trees
were
preserved in the north
side of the road. On the
southern side continue
tree plantations are
implemented along the
whole length of the
road.
Water
bodies
Evidence
Plantations to take
access
place
on
the All
embankments and embankments to the
bridges are planted
cuttings
with trees
New
drainage Drainage ditches were
and
ditches required as implemented
part of the road wetland plants are
proposals
would already growing on
in
several
provide wet areas ditches
for wetland plants, locations.
which will help
naturalising ditch
banks.
5-32
Mitigation
measure
Hedges
Proposed
Outturn
Replantation of hedgerows lost to The hedgerow plantation was successfully
carried out along most of the road length.
the south of the existing road.
The creation of new verges topped The wild flower plantation is not obvious to
with sub soil seeded with the visual inspection, however, this might
appropriate wild flower mixes to be a result of the autumn season.
increase the wildlife potential.
Scrub
Other verge areas could be
planted as scrub habitat to
increase the diversity of available
habitats. This would contain a mix
of Hawthorn, Blackthorn, Dog
Rose, Hazel and Goat Willow.
Hedgerows are substituted in some areas
with a mixture of species. The visit
identified among scrub, Hazel, Hawthorn
and Blackthorn.
Table 5.2 – Evaluation Summary Table
5-33
Evidence
Safety
5.10 The AST table for the A46 Newark-Lincoln improvement predicted significant accident
savings of 402 accidents and 21 fatalities of the project life, responsible for 34% of its
the scheme benefits in terms of present value.
5.11 In order to evaluate whether these predicted savings are likely we have undertaken an
initial evaluation of accident savings accrued from the new schemes after One Year
opening.
5.12 Normally, it is usual for accident savings to be evaluated at least three years after
opening in order to get a fair reflection in the number of accidents in the corridor,
therefore this evaluation for the One Year After Evaluation is an initial view and cannot
be considered as a firm conclusion at this time.
5.13 Despite this caveat, we have obtained accident data for three years prior to the scheme
opening. Table 5.3 below summarises the accident rates along the A46 between from
Winthrope and Hykeham roundabouts.
Accidents
per Year
Length
(km)
Road Type
AADT
(2-way)
pia/mvkm
Nat. Av.
pia/mvkm
A46 before improvement
22
13.04
Older S2 A-road
21,800
0.212
0.238
A46 after improvement
11
13.04
Modern D2 with HS
30,604
0.076
0.100
Section
Table 5.3 – Summary of Accident Data
5.14 The accident rate has dropped from 0.212 personal injury accidents (PIA) per million
vehicle kilometres (mvkm) to 0.076 PIA/mvkm. The national average accident rate for a
dual carriageway is 0.165 PIA/mvkm, which shows that the improvement schemes has
reduced the accident rate to below 50% of the typical rate for a road of this type.
5.15 We do stress again, however, that this is a One Year Evaluation, and firm conclusions
should really not be derived until at least three years after opening have elapsed, but the
initial signs are that the scheme has been successful in reducing accidents on the A46
improved section.
5.16 From the site visit it appears that substantial safety measures have been incorporated in
the scheme design. These include the provision of slip roads for gradual access to the
carriageways from the rest areas and farm access lanes, allowing heavy good vehicles
and tractors to speed up and smoothly joining the general traffic (Figure 5.1). On the
approach of the main roundabouts, skid resistant wearing course and horizontal band
strips provide warning and opportunity to slow down before approaching the
roundabouts as illustrated in the Figure 5.2.
5-34
Figure 5.1 – Slip roads for rural access
Figure 5.2 – Design of roundabout approaches
5-35
5.17 Within the AST, the predicted accident savings of the 30 year assessment period have
been reported, and in order to provide an initial view on the robustness of these
conclusions, we have predicted the number of accidents over the 30 year assessment
period.
5.18 In to predict the number of accidents that would have been foreseen by OPR
consultants, have they known the outturn traffic figures, we have assumed a
conservative 1% Growth in traffic each year, and a consistent accident rate of 0.08 with
the improvement and 0.21 without it, also assuming a 23,600 AADT average in 2004
with the improvement and 22,700 without it, this results in a total of 787 accidents
without the improvement and 312 accidents with the improvement, a saving of 475
accidents over the 30 year period, higher than the OPR predicted 402 accidents saved.
5.19 From COBA 10 we have the average severity split (that is, the number of fatal, serious
and slight casualties per accident). The 475 accidents reduction would save 12 deaths,
118 seriously and 609 slightly injured casualties.
Economy Impacts
5.20 As outlined in the previous section, Economy impacts are measured by changes in
journey times and traffic volumes on the A46 improved section, and on alternative
routes. The One Year After data show a reduction in journey times by 4 to 6 minutes
and a growth in traffic flows on average by 2% in the southern section of the
improvement and up to 8.7 % in the north near Thorpe, suggesting a major rerouting in
this section as well as generation from new developments.
5.21 While the link travel times have improved substantially above the predictions (15%
above), junction delays as well as operating costs have increased above the predictions
due to the higher traffic Growth than predicted, leading to an overall scheme economic
benefits slightly below the OPR predictions (3.2% less).
5.22 It is believed that such traffic is not sustainable in the future, which means that the
scheme economic benefits should improve in the future to the level of OPR predictions
or above. The evidence for this should come from the 5 Years After Study, where longer
term trends are established.
Accessibility & Severance Impacts
5.23 The A46 Newark-Lincoln improvement AST predicted that accessibility benefits would
accrue in terms of reduced severance in the village of Brough and ease of crossing the
A46 elsewhere for pedestrians and others.
5.24 Traffic volume in the de-trunked Fosse Way at Brough has dropped from 22,800 veh per
day to just below 400 veh per day, suggesting that the accessibility benefits outlined in
the AST are fair. All through traffic has transferred to the bypass which helped restoring
Brough village setting.
5.25 From the site visit it would appear that conditions have improved for pedestrians who
now can cross safely the main village road used solely by slow moving local traffic. This
is illustrated in the two photographs overleaf taken during a Friday morning visit to the
village.
5-36
5.26 The AST predicted that small accessibility benefits would accrue in terms of reduced
severance. The visit showed that all major village and farm accesses are provided with
access tracks and bridges, lessening farming severance.
5.27 Along the remainder of the route, severance has been mitigated by the provision of
roundabout junction at Thurby and grade separated junction at Thorpe, both offering a
full U-turning facilities.
Integration
5.28 The AST states that the planned 400 homes and more than 70 hectares of employment
land at RAF Swinderby site are likely to be dependent on the scheme. These have now
been implemented.
5.29 Phone interviews were carried out as part of this One Year After POPE assessment with
members of the development and planning policy teams within Lincolnshire and
Nottinghamshire County Councils in order to provide an initial feedback on their
perceptions of the impacts of the A46 scheme, One Year After Opening.
5.30 In Lincolnshire, the Regional Planning Guidance for the East Midlands identifies
Lincoln as a Principal Urban Area and seeks to significantly strengthen its regional role
over the next 20 years. In order to improve economic performance and reduce
deprivation in Lincoln it is envisaged that a greater proportion of housing, employment
and retail development should be provided in the area than previously experienced
based upon the need to promote sustainable patterns of development across the area.
5.31 Additional investment in transport provision will be vital in ensuring that the city and its
catchment area benefits from substantial new development in an environmentally
efficient manner. Key initiatives and proposals which are fundamental to unlocking
Lincoln's regional potential include the construction of the Lincoln Eastern Bypass coordinated with the development of a mixed-use sustainable urban extension located in
the north east quadrant of the city and alleviation of the severe traffic problems in central
Lincoln. It is hoped that improvements to the A46 will prove to be a catalyst which
5-37
assists with meeting these wider regeneration objectives for the Lincoln area in the longterm.
5.32 In Nottinghamshire, the bulk of housing within Newark & Sherwood district is occurring
in Newark Town and the improvement to the A46 assisted in improving movements
between Newark and commuter villages to the north such as Collingham, and wider with
those using services in Lincoln.
5.33 The main employment sites in Newark lie astride the northern end of the Town with
good links to the A1, A17 and A46. Again, the A46 improvement improved business
links to Lincoln and augmented the locational advantages of the industrial areas.
5.34 There is little direct housing associated with the A46 in Nottinghamshire.
5.35 In terms of Planning Policy within the two Counties, this will be considered further in the
Five-Year After assessment of the A46 scheme.
Summary
5.36 A summary of effects across all Evaluation Objectives are included in the EST Table 5.4
overleaf.
5-38
CRITERIA
ENVIRONMENTAL
Option: 2004 scheme - 12.9 km on-line D2 widening of existing A46 + bypass on Brough
SUB-CRITERIA
Noise
Actual Cost £25.9 m
QUALITATIVE IMPACTS
QUANTITATIVE MEASURE
ASSESSMENT
Benefits due to removal of through traffic from Brough.
IMPACT
no Noise complaints by the residents or statutory bodies
As forecast in the appraisal
Low traffic levels in Brough suggesting reduction in Noise
CO2
Local air quality
Benefits due to removal of through traffic from Brough.
tonnes added
no pollution complaints by the residents or statutory bodies
0-2000
Low traffic levels in Brough suggesting imrpovement in air quality
As forecast in the appraisal
Landscape
-
Neutral
Biodiversity
Substential plantation of Trees, Hedges, scrub, Hazel, Hawthorn and Blackthorn
Neutral
-
Heritage
Foss ways were protected.
Water
Drainage ditches were implemented
Neutral
-
Neutral
wetland plants are already growing on ditches in several locations.
SAFETY
-
Benefits due to separation of carriageways and removal of direct farm
Accidents Deaths Serious Slight
accesses.
ECONOMY
Journey times &
475
Journey times savings due to dualling providing opportunity to overtake.
12
118
peak
VOCs
4.5 mins
Cost
-
Reliability
609
PBV £18.2m
70% of PVC
interpeak
PVB £44.4m
6.5 mins
171% of PVC
-
Not re-assessed
PVC £25.9m
Slight
Low rel to PVC
Regeneration
Serves Nottinghamshire Development Objectives
Yes
Some downside effects on Lincolnshire - Longer commuting and Developments on Brown field
ACCESSIBILITY
Partly
Public transport
-
Neutral
Severance
Minimal - No complaints by resdients or statury bodies
-
Slight +ve
Pedestrians and
better crossing A46 with scheme.
-
Slight +ve
400 homes and >70ha land development at RAF Swinderbysite are implemented
-
Positive
others
INTEGRATION
-
COBA
PVB £62.5m PVC £25.9m NPV £36.7m BCR 2.4
Figure 5.4 – Evaluation Summary Table
5-39
6 Summary of Conclusions
6.1
The Highways Agency has a requirement to carry out re-evaluations of trunk road
schemes recently implemented by the Department of Transport. The purpose of these
re-evaluations is to provide a back check of the levels of benefit accruing from new
schemes and to determine how far the department achieves the objectives and
benefits it claims from its road programme.
6.2
In summary, the main points to note from the direct comparison of Pre and One Year
After scheme opening traffic volumes, travel times and accident records, are:

The bypass has been effective in relieving Brough village from through traffic
and transferring it to the A46 dual carriage way. The village has recorded around
98% reduction in traffic volumes from 26,0006 vehicles per day (vpd) in 2002
before construction began down to just below 400 vpd (on an average weekday).

A year after the improvement traffic volumes on the bypass amounted to 26,000
vpd on an average weekday of October. If the 400 vpd of local traffic in Brough
village is not taken into account as this most likely to be generated from
suppressed demand, traffic on the A46 at the level of Brough indicate a Growth
of 2%, in line with the national normal Growth levels.

Further north on the improved section, traffic volumes on the A46 near Thorpe
indicate a traffic Growth of 6.7% above the normal Growth, responsible for 1,800
extra vehicles per day. This is explained by traffic changes elsewhere, namely:

On the A1133 serving as alternative route between Newark and Lincoln, north
of the improvement, traffic volumes on Nottinghamshire County Council
permanent site, South of Langford have decreased by 700 vpd and on Atkins’
two weeks temporary site at Girton by 850 vpd.

On the A17-A607 route as southern alternative to A46 improvement, traffic
volumes on Atkins’ two weeks temporary site on the A17, east of Beckingham
have decreased by 3,100 vpd and on Lincolnshire County Council permanent
site, on the A607 Harmston south of Lincoln, have decreased by 600 vpds.


Such changes in traffic volumes suggest a rerouting of traffic from alternative
routes both north and south of the improved section, and occurring along the
northern section of the improvement (north of the bypass) only. This could be the
result of a combination of:

the improved access to the A46 from the adjacent rural areas, encouraging
rural traffic to take the A46 as their main access to the road network instead of
the A607 or the A1133, and

the new storage and delivery facilities recently built along the northern section
of the A46 improvement, south of Lincoln, attracted to the area by the A46
improvement.
Given that the improvement was an online dualling through the construction of a
new southern carriageway, traffic throughout the construction period was not
6
This is what would have happened in October 2004 without the scheme, obtained by adjusting the
average June 2002 daily traffic figures to account for traffic growth and seasonality.
6-40
disturbed and there was little or no effect on the route choice, timing and
frequency of trips, which explains the convergence of the traffic Growth with the
national average.

Journey Time savings of about 4.5 minutes (and up to 7 minutes) have been
observed in both directions and for all periods.

The assessment of travel speeds on the A46 between the A1 and the B1190
‘before’ and ‘after’ the A46 Newark Lincoln Improvement Scheme, shows that:
(i)
Typical journey speeds have increased from around 60kph to over 80kph;
and
(ii) Journey speeds are also consistent for all time periods after the opening of
the A46 Newark to Lincoln Improvement Scheme, showing that journey
time reliability will be sustained in the future.
6.3

In the three years prior to scheme opening, 66 accidents occurred on the A46
between the A1133 and A1434. The most common causes of accident were
collisions at roundabouts, junctions, and other shunts, while overtaking and
head-on collisions were relatively rare.

During the one year after opening, there were 11 accidents on the same section
of the A46 mostly single-vehicle accidents; however four of the six accidents
placed in this category also took place at roundabouts, so arguably accidents at
roundabouts could be the most important category.

In terms of accidents per unit length, the rural A46 is seen to have been safer
than the extensions NE and SW, which are urban. A further measure for
comparison based on “KSI7 Severity” showing the highest ratios on the A1 south
of A46, a fast dual carriageway, where the majority of accidents were Serious.

When traffic volumes (AADT) are considered, the annual accident rate for the
A46 Before was 0.212 Personal Injury Accidents per Million Vehicle Kilometres
(PIA/MVKM). The equivalent rate One Year After was 0.076, which is
significantly lower, as a result of both fewer accidents and despite the increase in
traffic volumes after opening.
The One Year After POPE assessment re-evaluated the scheme performance against
the five GOMMMS appraisal objectives. In summary, the main points to note are:
On the Economic Impacts

7
The scheme Economic impacts are measured by changes in journey times and
traffic volumes on the A46 improved section, and on alternative routes. While the
link travel times have improved substantially above the predictions (15% above),
junction delays as well as operating costs have increased above the predictions
due to the higher traffic Growth than predicted, leading to an overall scheme
economic benefits slightly below the OPR predictions (3.2% less). This is
summarised in the table overleaf:
the ratio of Fatal + Serious accidents to Total number of accidents
6-41
Predicted
Benefits
£m
Outturn
Benefits
£m
% Increase
£m
£51.28m
£49,64 m
-3.2%
Table 6.3 - Comparison of Economic Benefits for Low Growth

It is believed that the sudden growth in traffic is not sustainable in the future,
which means that the scheme economic benefits should improve in the future to
the level of OPR predictions or above. The evidence for this should come from
the 5 Years After Study, where longer term trends are established.

£25.913m, showing the outturn is 10% below predicted. Converting the predicted
costs into current prices (2004) and values results in a reduction of £46.911m
against outturn costs of £41.989m.
Construction
Land
Preparation &
Supervision
Total
predicted
£m
(2004 prices)
39.93
2.59
outturn
£m
(2004 prices)
36.86
2.57
4.39
46.911
2.56
41.989
Table 6.8 – Scheme Costs based on 2004 Prices and Values
On the Environmental Impacts

The environmental aspects of the A46 scheme have not been evaluated in detail.
The main premise for the benefits identified in the AST is that a great number of
the properties in Brough village will experience an improvement in air quality and
a decrease in the levels of noise generated by traffic. As the traffic reduction in
the village and traffic levels on the bypass are in line with the forecasts it is fair to
say that the environmental impacts reported in the AST are likely to have been
achieved.

The One Year After evaluation did not reassess the noise and air quality around
the affected properties. However, to our knowledge no complaints have been
made by the residents or environmental statutory bodies.

As for the forecast negative impacts on landscape, biodiversity and water, the
One Year After site visit surveyed the route and checked that the implementation
of the mitigation measures is progressing as claimed in the Environmental
Statement.
6-42
On the Accessibility & Severance Impacts

Traffic volume in the de-trunked Fosse Way at Brough has dropped from 22,800
veh per day to just below 400 veh per day, suggesting that the accessibility
benefits outlined in the AST are fair. All through traffic has transferred to the
bypass which helped restoring Brough village setting.

From the site visit it would appear that conditions have improved for pedestrians
who now can cross safely the main village road used solely by slow moving local
traffic.

Along the remainder of the route, severance has been mitigated by the provision
of roundabout junction at Thurby and grade separated junction at Thorpe, both
offering a full U-turning facilities.
On the Integration

The planned 400 homes and more than 70 hectares of employment land at RAF
Swinderby site are implemented.

In Lincolnshire, new developments for storage and distribution, taking
advantage of the better access/logistics enabled by the improvement and the
loss of interest on redeveloping brown fields within Lincoln city. Such
developments are increasingly important to support industry (mainly the food
production) and commerce. They generate low levels of employment density but
significant lorry movements. The dualling of the A46 between Lincoln and
Newark may lead to pressure such developments outside urban areas in green
fields, contrarily to what the structure plan aims for their location within
brownfield sites in urban areas. Also linked to the scheme, developments such
as car show centres and leisure centres, e.g. around North Hykam catering for
the implemented massive housing development. Thus the scheme may counter
act the efforts of Local Authorities for Self Containment and stabilisation of the
local population by providing opportunities for commuting to/from areas further
away. Currently 13,000 locals commute from Lincoln to other work locations.

In Nottinghamshire, the bulk of housing within Newark & Sherwood district is
occurring in Newark Town and the improvement to the A46 assisted in improving
movements between Newark and commuter villages to the north such as
Collingham, and wider with those using services in Lincoln. The main
employment sites in Newark lie astride the northern end of the Town with good
links to the A1, A17 and A46. Again, the A46 improvement improved business
links to Lincoln and augmented the locational advantages of the industrial areas.
6-43
Appendix A – Journey Times on the A46 Improvement
Before (June 2002)
Av. Time
Taken
Route
Red Route - (A46 Route) A1 / A17 Newark - A46 / A57
Lincoln
Red Route - (A46 Route) A46 / A57 Lincoln - A1 / A17
Newark
Blue Route - (A17 / A607 Route) A1 / A17 (Newark) - A607 /
A1434 (Lincoln)
Blue Route - (A607 / A17 Route) - A607 / A1434 (Lincoln) A1 / A17 (Newark)
Orange Route - (A57) - B1190 Thorney - A46 North-east of
Lincoln
Orange Route - (A57) - A46 North-east of Lincoln - B1190
Thorney
Yellow Route - A46 / A1133 Newark - B1190 / A1434
Lincoln(via A1133/A57/B1190)
Yellow Route - B1190 / A1434 Lincoln - A46 / A1133 Newark
(via A1133/A57/B1190)
Direction
North Bound
North Bound
North Bound
South Bound
South Bound
South Bound
To Lincoln
To Lincoln
To Lincoln
To Newark
To Newark
To Newark
East Bound
East Bound
East Bound
West Bound
West Bound
West Bound
North Bound
North Bound
North Bound
South Bound
South Bound
South Bound
Period
AM Peak
Inter Peak
PM Peak
AM Peak
Inter Peak
PM Peak
AM Peak
Inter Peak
PM Peak
AM Peak
Inter Peak
PM Peak
AM Peak
Inter Peak
PM Peak
AM Peak
Inter Peak
PM Peak
AM Peak
Inter Peak
PM Peak
AM Peak
Inter Peak
PM Peak
(mm:ss)
17:36
17:15
17:43
17:46
19:06
17:17
28:56
27:42
29:08
29:27
28:28
29:56
27:26
28:17
28:03
25:56
24:36
26:59
31:34
29:55
32:12
28:55
28:02
30:16
After (Sept 03)
Difference - Sept 03
Av. Time
Av. Speed
(Kph)
61
63
61
61
57
62
73
77
73
72
75
71
68
66
66
72
76
69
64
67
62
70
72
66
Taken
(mm:ss)
13:32
12:41
13:14
13:29
12:23
12:39
36:20
35:01
37:29
35:32
34:38
35:21
30:41
27:36
28:15
26:34
28:03
27:25
33:45
32:33
35:48
33:35
33:11
33:54
Av. Speed Av. Time
(Kph)
Saving
80
04:04
85
04:34
82
04:28
80
04:16
87
06:43
85
04:38
58
-07:23
61
-07:19
57
-08:21
60
-06:05
61
-06:10
60
-05:25
61
-03:15
67
00:41
66
-00:12
70
-00:38
66
-03:28
68
-00:26
60
-02:11
62
-02:38
56
-03:36
60
-04:40
61
-05:09
59
-03:37
Results of Journey Time Surveys on ‘Red’, ‘Blue’, ‘Orange’ and ‘Yellow’ Routes
44
A. Speed
Difference
18
23
21
19
31
23
-15
-16
-16
-12
-13
-11
-7
2
0
-2
-9
-1
-4
-5
-6
-10
-11
-7
45

A46 Newark - Lincoln Improvement ONE YEAR AFTER STUDY

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