Success Stories • In
1997, Metro, the regional government in Portland, Oregon adopted
new regional street design guidelines as part of its growth
plan for 2040 and its Transportation Policy Plan. The new standards
better accommodate multiple modes of travel and support the regional
land use plan by classifying roads in three major categories:
- Highways
and roads—facilities with a primary focus on vehicle
traffic and regional mobility;
- Boulevards—facilities
oriented to pedestrian, bicycle, and transit modes of travel;
- Streets—facilities
that provide a balance between all modes of travel (3).
The
new street classification system is the accepted standard for all
communities within the region and a portion of the
region’s
federal transportation funds are set aside to encourage reconstruction
of boulevards. Portland’s classification system is consistent
with nationally accepted road
design standards (AASHTO) (4).
• The
Linden Hills
neighborhood in Minneapolis used traffic-
calming measures to improve
the pedestrian environment in its business district.
With funding and technical assistance from the Minneapolis Neighborhood
Revitalization
Program, the neighborhood planned for and implemented pedestrian-friendly
measures including: traffic circles, sidewalk extensions at intersections,
boulevard trees, and wider sidewalks. The planning process included
hundreds of residents and business owners (5). The City of Minneapolis
also created a Traffic Calming Guide for neighborhoods.
The Linden Hills neighborhood in Minneapolis
has made many investments to improve the pedestrian environment
• The Federal
Highway Administration (FHWA) is promoting Context
Sensitive Design as a solution to designing road projects
that are more responsive to community and environmental needs. FHWA’s
1997 publication, Flexibility in Highway Design, encourages engineers
to increase public involvement in road planning and allow for
greater flexibility within the national guidelines.
• The
city of Saint
Paul changed the lane configuration of
a number of municipal roads to reduce vehicle speed and crashes,
and to provide
a safer environment for bicycles and pedestrians. The city converted
a number of four-lane roads to two-lane roads with a center left-turn
lane. Since 1999, when Fairview Avenue was changed from four lanes
to three, accidents declined by more than 50 percent and speeding
was reduced by more than 40 percent (6).
• A
study by the Institute of Traffic Engineers showed that traffic
calming measures can slow traffic, divert cut-through traffic,
and reduce crash rates - increasing pedestrian and bicycle safety
(7). In Seattle, 700 traffic circles have been installed since
1973. After
implementing its citywide traffic-calming program, Seattle reported
a 77-91 percent reduction in vehicle collisions (8).
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Minnesota
has no guidebook or manual that explains in lay person’s terms
the complex process of road design. This makes it difficult for interested
citizens, impacted property owners,
or sometimes even city officials to understand and effectively participate
in planning for roadway construction or reconstruction. Road design standards depend on the type of road (functional classification),
the jurisdiction that owns the road, and where the funding comes from
for construction or maintenance. The design of a road is governed by
four factors:
- The
location of the road, e.g., whether it is urban, suburban or rural.
- The
functional classification of the road. Roads are classified into
different types – local, collector, arterial, and gradations
of each. The higher the road classification, the higher or larger
the design
standards for such things as speed, lane width and shoulder width.
- The
projected Average Daily Traffic (ADT) or number of vehicles projected
to use the road on an average day at the end of a 20-year planning
horizon. The greater the expected vehicle traffic, the greater the number
of lanes,
the wider the lanes and shoulders, and the more likely that turn
lanes will be required.
- The
design speed of the road. Road design standards specify higher
design speeds for roads that are flat or multi-lane,
in rural
areas, or with
higher traffic volumes (MnDOT Road Design Manual section 2-5.07).
See “Vehicle
Speed” below for more information on this subject.
When new roads are built, or older roads reconstructed, they are typically
designed to accommodate projected traffic volumes up to 20 years in the
future. This can result in roads that are too large for current traffic
volumes, or actually encourage more traffic through an area as motorists
take advantage of a larger, less congested road.
Roads usually are designed for speeds 5 to 10 mph above the posted speed
limit in order to increase motorist safety by providing a margin of error.
The design speed can be increased by widening or straightening a road,
smoothing a grade or providing wide visibility. The faster traffic that
inevitably results can make roads less safe for pedestrians and bicyclists.
Road design and reconstruction in older urban areas
Many
existing arterial streets in older communities were built with
narrower lanes and shoulders than today’s standards require.
Widening these roads to meet current standards can result in the removal
of boulevard space and boulevard trees, the narrowing of
adjacent sidewalks, or the elimination of on-street parking.
While
a variance process is available for state aid roads, communities often
find it to be time-consuming and complicated. Cities and counties
report being reluctant to ask for a variance because they assume greater
liability for the road if a variance is granted (1). Traffic flow vs. pedestrian safety
Sometimes
road “improvements” mean reduced safety for pedestrians
and bicyclists. For example, new roads typically must be designed for
a certain level of vehicular traffic flow or mobility, called “vehicle
level of service” (LOS). In order to achieve the required level
of service, engineers may add turn lanes at intersections or change the
timing of traffic signals to keep traffic moving and prevent congestion.
This improves the level of service for vehicles, but can decrease it
for pedestrians by increasing crossing distances and extending pedestrian
wait times at signals.
Local Streets
The
primary purpose of local streets is to provide access to homes, neighborhood
parks and shopping, but the way those streets are designed
also impacts a neighborhood’s character. When local streets are
narrow and traffic is slow, it improves people’s feeling of safety
and increases social interaction.
Ford Parkway in Saint Paul. Saint Paul has converted a
number of roads from four lanes to two with a center left-turn lane,
and accident rates and speeding have declined. This design is encouraged
by MnDOT.
Local streets in older communities tend to be narrower, with adjacent
sidewalks for pedestrians, on-street parking and alleys for vehicle access
to residences. On-street parking often slows traffic and provides a safety
buffer for pedestrians on the sidewalk. In newer communities, residential
streets tend to be wider, they lack sidewalks, and are shared by pedestrians
and vehicles.
In
2002, the city of Bloomington, Minnesota, reduced its standard width
for residential streets from a minimum of 36 feet to a minimum of 28
feet, with a maximum of 32 feet. The new standard will be used to retrofit
about 5 percent of the city’s residential streets with curb and
gutter (the remaining 95 percent already have been rebuilt and widened
to 36 feet). Bloomington found that the reduced widths saved 10 percent
in street reconstruction costs and reduced vehicle speeds (2).
Recommendations
- Accommodate
pedestrian and bicycle travel as standard practice in the design
of road projects.
- Revise
state, county, and municipal road design standards to allow for the
construction and reconstruction of roads
to reflect existing
and planned land uses and to better balance the needs of vehicle drivers
with bicyclists, pedestrians, and transit users.
- Revise
regional road classifications to reflect existing and planned land
uses and
to better balance the needs of vehicle drivers with bicyclists,
pedestrians, and transit users.
- Provide
training for road planners and engineers on best
practices in designing for bike and pedestrian travel.
- Promote
and use existing state guidelines for developing bicycle
facilities, and develop and promote similar resources for pedestrian
facilities.
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Footnotes
1 Bob Brown, MnDOT, e-mail communication with S. Peterson, 12 Feb. 2003.
2 Steve Elkins, Bloomington City Council member, phone interview by S.
Peterson, 8 Jan. 2003.
3 Metro, “Street Design Guidelines for 2040,” (Portland, OR,
Metro Regional Services: 1997), 2.
4 Ibid.
5 Madeline Cioci, Linden Hills Neighborhood Council, phone interview with
Ben Owen, 3 May 2002.
6 Al Shetka, City of Saint Paul, internal e-mail, 7 June 2000.
7 Institute of Traffic Engineers, “Traffic Calming: State of the
Practice,” Aug. 1999. Accessed from www.ite.org/traffic/testate.htm.
8 “Safe Routes to Schools,” p. 2, www.transact.org/ca/saferoute/saferoute.htm.
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