Present

2011 Analysis of the Safety Impact of Quiet
Zones at Highway-Rail Grade Crossings
Interest in Quiet Zones Remains
High

Currently there are
◦ 165 Pre-Rule quiet zones
◦ 293 New quiet zones
◦ 76 Notices of Intent
18 quiet zones have been identified by
FRA as no longer being qualified since
2008 (QZRI too large)
 Question – Have quiet zones negatively
impacted safety?

Contents
 Data
Collection
Eliminated Data
 Collision
Data
Selected
 Study Methodology
 Data Analysis
 Results
 Conclusion
 Next Steps
This presentation will
cover the results of
research performed to
determine whether or
not quiet zone
implementation has had a
negative impact on
crossing safety.
Qualifying Conditions
Supplemental Safety
Measures (SSMs) must be
put into place at all public
crossings.
The QZRI is less than or
equal to the NSRT without
additional safety measures.
Alternative Safety Measures
(ASMs) are taken to reduce
the QZRI so that is it less
than or equal to the RIWH
or the NSRT. May include
SSMs.
SSMs are installed at certain
crossings to ensure that the
QZRI is less than or equal
to the NSRT or the RIWH.
Data Collection
CCM Data Base
GCIS and RAIRS
•contains all of the relevant information
about a quiet zone.
•includes a train horn rule number assigned
to a quiet zone
•identifies how the quiet zone was
established (BasSection ) and the QZ Type
(Pre-Rule or New) in a searchable and
downloadable database
The Grade Crossing Inventory System
(GCIS) contains information on all
crossings and was used to identify the
characteristics of the individual crossings
within the quiet zone.
Railroad Accident Incident Reporting
System (RAIRS) contains information on
how many incidents have occurred at
particular crossings and the details of those
incidents.
Data Collection
Quiet Zones (observed)
5%
New (188)
52%
New Partial (5)
Pre Rule (148)
Pre Rule Partial (18)
41%
2%
75 Quiet Zones were eliminated
• (73) Data Elements with less than 1 year of comparative data
• (2) No Valid NOE date
359 Quiet Zones in the study pool
Data Used
Group
Established
Between
Months of
Data
Total Quiet
Zones
Pre NOE
Incidents
Post NOE
Incidents
1
Jun-05
Jan-06
60
178
124
121
2
Feb-06
Jan-07
48
36
9
11
3
Feb-07
Jan-08
36
45
22
27
4
Feb-08
Jan-09
24
50
8
10
5
Feb-09
Jan-10
12
50
5
2
6
Feb-10
Present
Not Included
Not Included
• 12 months increments to eliminate seasonal variations
• May have been collisions outside the 12 month periods
Data Analysis: Grouping Data
Group Established Between
1
2
3
4
5
6
Group
1A
Jun-05
Feb-06
Feb-07
Feb-08
Feb-09
Feb-10
Jan-06
Jan-07
Jan-08
Jan-09
Jan-10
Present
Established Between
Jun-05
Jan-06
Consecutive
months of data
Number of
QZs in group
60
48
36
24
12
178
36
45
50
50
Not Included
Consecutive
months of data
60
Number of QZs
in group
158
Only
20
QZs
are
New!
Study Methodology: Hypothesis
Hypothesis
• Our hypothesis is that there will be no statistical difference between the
number of incidents that occurred before the quiet zone was established
and the number of incidents that occurred after the quiet zone was
established (due to the installation of SSMs/ASMs compensating for the lack
of a train horn).
If P-value = 1 − P(|T| ≤ |t|) > α = 0.05 then do not reject H0; otherwise reject H0
In English…
 A t-test tells us whether or not there is a statistical
significance between incidents that occurred before
and after the quiet zone was established. If the test
results in a number greater than .05 then we cannot
reject our hypothesis.
NOTE: Failure to reject the hypothesis DOES NOT mean acceptance
Data Analysis: Other Comparisons
BasSection
The Rule section in 49 CFR 222
by which the QZ established.
Motorist Vehicle Type
The type of vehicle the
motorist was driving
Pre Rule vs. New QZs
Comparisons of Pre-rule quiet
zones to New quiet zones
Motorist Actions
What, if anything, the motorist
did to cause the incident
Data Analysis: Raw Data
Group
Observations
(# of QZs)
Pre-QZ
Incidents
# Incidents
per Pre-QZ
Post-QZ
Incidents
# Incidents
per Post-QZ
1
178
130
0.7303371
124
0.69662921
1A
158
121
0.7658228
115
0.7278481
2
36
9
0.25
11
0.30555556
3
45
22
0.4888889
27
0.6
4
50
8
0.16
10
0.2
5
50
7
0.14
4
0.08
TOTAL
517
176
176
Red indicates a larger number of incidents per quiet zone
Data Analysis: How Established
BasSection
RP – not auto 222.41(c)
qualified
PR – part – auto – QZRI<2*NSRT
222.41(b)(1)(iii)
PR – part – auto – 222.41(b)(1)(ii)
QZRI<NSRT
PR – auto – 222.41(a)(1)(iv)
QZRI<RIWH
PR – QZRI<2*NSRT
222.41(a)(1)(iii)
PR – 222.41(a)(1)(ii)
QZRI<NSRT
PR – SSMs at222.41(a)(1)(i)
all crossings
New – ASMs222.39(b)(4)(i)(B)
– QZRI<NSRT
New – ASMs 222.39(b)(4)(i)(A)
– QZRI<RIWH
New – SSMs – QZRI<RIWH
222.39(a)(3)
New – SSMs – 222.39(a)(2)(ii)
QZRI<NSRT
New – SSMs – QZRI<NSRT
222.39(a)(2)(i)
New – SSMs at all222.39(a)(1)
crossings
0
10
20
30
Post NOE
40
Pre NOE
50
60
70
Data Analysis: Motorist Actions
Post Quiet Zone
Pre Quiet Zone
Stopped
then
proceeded
8%
Blank
entry
8%
Other
9%
Stopped on
Crossing
27%
Other
14%
Did Not
Stop At
Crossing
33%
Drove
Around
15%
Did Not
Stop At
Crossing
27%
Blank entry
13%
Stopped
then
proceeded
7%
Stopped on
Crossing
18%
Drove
Around
21%
The Results…
Group
Established
Between
P(T<=t) two-tail
P-value
Is P-value > α = .05?
1
Jun-05
Jan-06
0.735133829
0.264866 Yes, DO NOT REJECT
1A
Jun-05
Jan-06
0.682911782
0.317088 Yes, DO NOT REJECT
2
Feb-06
Jan-07
0.643923821
0.356076 Yes, DO NOT REJECT
3
Feb-07
Jan-08
0.441065902
0.558934 Yes, DO NOT REJECT
4
Feb-08
Jan-09
0.674229012
0.325771 Yes, DO NOT REJECT
5
Feb-09
Jan-10
0.410872385
0.589128 Yes, DO NOT REJECT
Conclusion
QUIET
ZONE
Individual tests demonstrate that among
each of the groups there was no statistical
significance that would indicate that the
observed locations were less safe because
of the establishment of the Quiet Zone and
therefore the null hypothesis cannot be
rejected.
Next Steps
Do this analysis on a yearly basis
 Look at different aspects of the data

◦ At which crossings are the collisions
occurring?
◦ SSMs/ASMs

Are there other methods of analysis that
could be used?
Thank you to Marquese Lewis
who performed the study.
Questions??
Ron Ries
(202) 493-6285
[email protected]