Road DesignSusan Handy

TTP Orientation SeminarOctober 2015

Level Agencies Primary concern

Primary role

Federal FHWAFTA

National Highway System

FundingPolicy

State DOT Highways outside metro areas

PlanningBuildingOperating

Regional MPOTransit

Highways, transit within metro areas

Planning

Local PlanningPublic Works

Local streets

PlanningBuildingOperating

Road Design in the U.S.

Manuals and Guidelines from FHWA and state DOTs, also from… AASHTO – American

Association of State Highway and Transportation Officials

ITE – Institute of Transportation Engineers

NACTO – National Association of City Transportation Officials

Topics

• Network design• Facility design• Plus others

Network Design

• What are the two main purposes of streets/roads/highways?

• What’s the main difference between streets vs. roads vs. highways?

Source: http://ops.fhwa.dot.gov/access_mgmt/what_is_accsmgmt.htm

The Road Hierarchy

National Committee on Urban Transportation, 1958

City of Sunnyvale, 1957

ITE Street Layout Principles, 1984

City of Austin, Comprehensive Plan, 1994

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

• More choice of routes…

Connectivity MeasuresSource: Peter Owens

Source: Handy, Paterson, and Butler 2003

Source: Handy, Paterson, and Butler 2003

Source: http://www.fotosearch.com/photos-images/cul-de-sac.html

http://www.citylab.com/housing/2013/10/sociologists-defense-cul-de-sac/7262/

Berkeley Diverters

Source: http://www.ci.berkeley.ca.us/transportation/Bicycling/BB/BicycleBoulevardTreatments.html

Village Homes, Davis

Source: Google Maps

Davis Greenbelt System

Source: Google Maps

Houten, Netherlands

Source: Google Maps

Let’s see some images from Susan’s visit in September 2012…

Facility DesignResponsibility Influence

Local Streets Cities and counties

ITE –Institute of TransportationEngineers

Highways and Freeways

State DOTs AASHTO –American Association of State Highway Officials

Institute of Transportation Engineers

http://www.ite.org/bookstore/RP-011C.pdf

Right-of Way – Cross-Section

http://www.ite.org/bookstore/RP-011C.pdf

Specified Dimensions for ROW

https://bookstore.transportation.org/item_details.aspx?ID=110

The Green Book

Wide Streets

All over Davis, and elsewhere

Innovations/Trends

• Skinny Streets• Traffic Calming• Road Diets• Complete Streets• Green Streets• Context-Sensitive Design• Others…

Skinny Streets

Canyon Rim Village, Medford

http://darkwing.uoregon.edu/~cpw/projects/pdf/featured/tgm_2003/powerpoints/366,11,Narrow Streets

Traffic Calming

"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

Types of Traffic Calming

Speed Control Measures

Volume Control Measures

DivertersRestrictions

Vertical deflectionspeed bumpsraised crosswalks

Horizontal deflectiontraffic circleschicanes

Horizontal narrowingbulb-outs, neck-downs, curb extensions

Speed bump

Raised crosswalk

Traffic circle

Chicanes

Bulb-outs

Woonerfs – Home Zones

Road Diet

Source: http://www.buryinc.com/blog/2012/08/10/the-road-diet/

Road Diet

Source: http://www.bicycletucson.com/news/university-bikeped-study-released/13438

Fifth Street Road Diet in Davis: Many years in the making!

Complete Streets

http://la.streetsblog.org/wp-content/uploads/2008/10_06/10_8_08_complete_streets.jpg

Complete Streets

Source: http://www.metrojacksonville.com/article/2010-mar-complete-streets-policy-to-impact-jacksonville

Green Streets

Marcy McInelly, SERA/Urbsworks

Green Streets

Sources: www.museumofthecity.org; http://www.mwcog.org/transportation/weeklyreport/2013/06-04.asp

National Association of City Transportation Officials

Institute of Transportation Engineers

“Context-Sensitive Design”

Source: http://www.dot.ca.gov/hq/oppd/context/main-streets-flexibility-in-design.pdf

Texas-Style

Sources: http://www.slate.com/articles/life/transport/features/2010/unbuilt_highways/san_francisco_the_embarcadero_freeway.html

Freeway Removal

Road Design Conundrum

Crash risks minimized but high speeds

Crash risks remain but low speeds

Parking!

Parking Problems

• Minimum parking requirements for residential and commercial development, in zoning codes– Excess parking and thus pavement

and thus heat, run-off, etc.

• Free curbside parking in central business districts– Excess driving – “cruising” to find

spaces – and thus emissions See Don Shoup’s work!

Traffic Management

• Approaches:– Traffic control devices to

regulate behavior– Roadway design to shape

behavior

• Goals: – Safety– Efficiency– Plus livability!

Source: http://mutcd.fhwa.dot.gov/pdfs/2003r1/pdf-index.htm

MUTCD

MUTCD Principles

• Purpose is “… to promote highway safety and efficiency by providing for the orderly movement of all road users… throughout the Nation…”

• “The decision to use a particular device at a particular location should be made on the basis of either an engineering study or engineering judgment…”

• Not a legal requirement• Not a substitute for engineering judgment

Speed Limits

• MUTCD section 2B-10 (update: 2B-13) requires that the numeric value be determined on basis of an engineering study. The following factors should be considered:1. Road surface characteristics, shoulder condition, grade, alignment and

sight distance. 2. The 85-percentile speed and pace speed. 3. Roadside development and culture, and roadside friction. 4. Safe speed for curves or hazardous locations within the zone. 5. Parking practices and pedestrian activity. 6. Reported accident experience for a recent 12-month period.

For a discussion, see: http://www.motorists.org/speed-limits/safety-setting-limits

Level of Service

TRB’s Highway Capacity Manual

LOS = f (volume/capacity) How to increase LOS?

Result: Massive Intersections

Next up: Paul Erickson on vehicle technology