Road Design

Road Design
Susan Handy
TTP Orientation Seminar
October 2010
Topics
• Network design
• Facility design
Transportation Planning in the U.S.
Level
Agencies
Primary
concern
Roles
Federal
FHWA
FTA
National
Highway
System
Policies – planning process
Funding – highways, transit, other
Programs – e.g. bikes and peds, livable
communities, etc.
State
DOT
Highways
outside
metro
areas
Policies – State Transportation Plan, TIP
Funding – federal match, state programs
Implementation – construction, maintenance
Regional
MPO
Transit
Highways,
transit
within
metro
areas
Policies – Regional Transportation Plan, TIP
Funding – local sales tax
Implementation – transit system and operations
Local
Planning
Public
Works
Local
streets
Policies – General Plan, capital improvements
Funding – general revenues, special taxes
Implementation – construction, maintenance
Network Design
• What are the two main purposes of
streets/roads/highways?
• What’s the main difference between streets
vs. roads vs. highways?
National Committee on Urban Transportation, 1958
City of Sunnyvale, 1957
ITE Street Layout Principles, 1984
City of Austin, Comprehensive Plan, 1994
Connectivity Measures
Benefits of grid…?
• More direct routes
– Less distance
• Less driving (?)
– Less pollution, energy consumption, noise, etc.
• More walking/biking
– More exercise, less weight, better health, etc.
– Better efficiency
• Emergency response time
• City services
Source: Handy, Paterson, and Butler 2003
Source: Handy, Paterson, and Butler 2003
Source: http://www.fotosearch.com/photos-images/cul-de-sac.html
Berkeley Diverters
Source: http://www.ci.berkeley.ca.us/transportation/Bicycling/BB/BicycleBoulevardTreatments.html
Village Homes, Davis
Source: Google Maps
Davis Greenbelt System
Houten, Netherlands
Source: Google Maps
Source: Google Maps
Facility Design
• Responsibility for building:
– City/County: local streets, collectors, arterials
– State: highways, freeways
• Influence on professional practice:
– Institute of Transportation Engineers (ITE)
– American Association of State Highway and
Transportation Officials (AASHTO)
http://www.ite.org/bookstore/RP-011C.pdf
http://www.ite.org/bookstore/RP-011C.pdf
http://www.ite.org/bookstore/RP-011C.pdf
Source: http://www.ashland.or.us/Files/street%20standards_001.pdf
Source: http://www.ashland.or.us/Files/street%20standards_001.pdf
Source: http://www.ashland.or.us/Files/street%20standards_001.pdf
Source: http://www.ashland.or.us/Files/street%20standards_001.pdf
Innovations/Trends
•
•
•
•
•
•
•
Traffic Calming
Skinny Streets
Road Diets
Complete Streets
Green Streets
Context-Sensitive Design
Others…
Traffic Calming
Communities Featured in Report
Seattle
Bellevue
Boulder
Dayton
Portland
Eugene
Howard Co.
Montgomery Co.
Charlotte
Gwinnett Co.
Berkeley
San Jose
San Diego
Phoenix
Austin
Ft. Lauderdale
Tallahassee W. Palm Beach
Gainesville
Sarasota
"Traffic calming is the combination of mainly physical measures that reduce the
negative effects of motor vehicle use, alter driver behavior and improve
conditions for non-motorized street users."
- ITE Subcommittee on Traffic Calming
Speed Control Measures
Vertical Deflection
Horizontal Deflection
Horizontal
Narrowing
Other Measures
Speed Humps
Traffic Circles
Neckdowns
Examples
Speed Tables
Roundabouts
Center Island
Narrowings
Raised Crosswalks
Chicanes
Chockers
Raised Intersections
Realigned Intersections
Textured Pavements
Speed Lumps *
Speed Cushion *
Split Speed Hump *
Volume Control Measures
Divertive, Restrictive
Other Measures
Full Closures
Examples
Half Closures
Diagonal Diverters
Lateral Shift *
Median Barriers
http://www.trafficcalming.org/measures2.html
Traffic Circles
http://www.trafficcalming.org/measures2.html
Roundabouts
Chicanes
http://www.trafficcalming.org/measures2.html
Neckdowns
Narrow Street Scenarios
http://darkwing.uoregon.edu/~cpw/projects/pdf/featured/tgm_2003/powerpoints/285,13,Narrow Street Scenarios
Narrow Streets
Canyon Rim Village, Medford
http://darkwing.uoregon.edu/~cpw/projects/pdf/featured/tgm_2003/powerpoints/366,11,Narrow Streets
Road Diet
Evaluation of Fifth
Street Road Diet in
Davis:
Mode split to
downtown and
bike/ped safety before
and after
Complete Streets
http://la.streetsblog.org/wp-content/uploads/2008/10_06/10_8_08_complete_streets.jpg
Green Streets
Marcy McInelly, SERA/Urbsworks
https://bookstore.transportation.org/item_details.aspx?ID=110
“Context-Sensitive Design”
Source: http://www.dot.ca.gov/hq/oppd/context/main-streets-flexibility-in-design.pdf
Riverfront Parkway and
Downtown Streets, Chattanooga, TN
Roadway Modifications
Image: City of Chattanooga and River City Company
Riverfront Parkway, Chattanooga, TN
“Before” Conditions
Image: City of Chattanooga and River City Company
Reconstructed Riverfront Parkway
Image: City of Chattanooga
Next up: Vehicle Technology