HomeMy WebLinkAboutRoad-Diets-Fact-SheetRoad Diets | A LIVABILITY FACT SHEET
Most drivers base their travel speed on what feels
comfortable given the street design. The wider the road,
the faster people tend to drive and, the faster the car, the
more severe the injuries resulting from a crash.1
Research suggests that injuries from vehicle crashes rise as
the width of a road increases.
To protect both pedestrians and drivers, many
communities are putting their roads on “diets“ by reducing
street widths and vehicle lanes. The gained space is being
reallocated toward other ways of getting around — such
as walking, bicycling and public transit.
The most common road diet involves converting an
undivided four-lane road into three vehicle lanes (one lane
in each direction and a center two-way left-turn lane).2 The
remaining fourth lane space can be used to create such
features as bicycle lanes, pedestrian crossing islands, bus
stops, sidewalks and on-street parking.3
Road diets work best on streets that have daily traffic
volumes of 8,000 to 20,000 vehicles. When done properly,
a road diet improves the performance and efficiency of
the street and makes it safer for all users.
For instance, by enabling pedestrians to cross only one
lane of traffic at a time — rather than up to four or more
lanes — a road diet reduces the risk of crashes and serious
injuries. At the same time, motorists experience a shorter
delay while waiting at traffic lights and other crossings.4
A road diet can help a neighborhood become a more
desirable place to live, work and shop, which in turn can
be a boost to businesses and property values.
Wider sidewalks lined by trees and dotted with benches,
bicycle racks, streetlights and other useful additions help
create a lively, attractive streetscape.
Bike lanes, on-street vehicle parking, curb extensions and
“parklets” (tiny parks created from former parking spots)
can be used to provide a buffer between people who are
walking and motor vehicles on the move.
In addition to making East Boulevard in Charlotte, N.C., more attractive, a road diet reduced travel speeds,
bicycle and pedestrian injury rates and the number of rear-end and left-turn collisions. Photo courtesy city of Charlotte
By enabling pedestrians to cross only one lane of traffic at a time — rather than up to
four or more lanes — a road diet reduces the risk of crashes and serious injuries.
Myth-Busting!
“Road diets divert traffic.”
Drivers tend to use primary roads that provide the most
direct and efficient route to a destination.
Well-designed road diets do not divert drivers onto
other roads. While traffic often drops during construction,
it typically returns to normal or increases within six
months of completion. Many roads actually experience an
increase in vehicle traffic after a successful diet.5
“Road diets increase congestion.”
On roads used by fewer than 20,000 vehicles per day,
road diets have a minimal or positive impact on vehicle
capacity. Left-turning vehicles, delivery trucks, police
enforcement and stranded vehicles can move into a center
lane or bike lane, which eliminates double-parking and
reduces crash risks.6
“Road diets increase crashes.”
Road diets actually reduce rear-end collisions and
sideswipe crashes by slowing vehicle speeds by 3 to 5
mph. Road diets decrease by 70 percent the frequency of
people driving more than 5 mph over the speed limit.
Data collected on road diets in two very different
settings (several small towns in Iowa and a group of larger
cities and suburbs in California and Washington state)
confirmed that road diets improve safety. The research
showed a 47 percent reduction in crashes in the Iowa
towns and a 19 percent drop in crashes in the more
heavily traveled corridors of California and Washington.7
“Road diets aren’t good for public transit.”
Transit conflicts can be avoided with planning, such as by
incorporating a center lane so motorists can move around
stopped buses and adding side pull-out bays for buses.8,9
“Road diets are bad for business.”
Road diets increase and enhance business activity by
reducing traffic speeds (which helps motorists notice the
shops, eateries and businesses they’re driving alongside)
and by accommodating pedestrians and bicyclists (who,
by the way, tend to spend more money at local businesses
than drivers do).10
Road diets often create more street parking spaces,
which is helpful to businesses. In addition, the slower
speeds, better sight lines and narrower lanes are safer for
both drivers and non-drivers (aka customers), and center-
turn lanes provide motorists with an easier and safer way
to make right and left turns, including for entering and
exiting driveways. 11
“Road diets are being reversed.”
With thousands of road diets completed nationwide, there
are few reports of any being reversed. On the contrary,
road diets are proving to be effective, safe and popular.
Interest among transportation engineers and planners is
booming as handbooks, guidelines and other resources
become available.12
“Road diets slow down emergency responders.”
By not using short speed humps and stop signs, a road
diet can accommodate emergency vehicles without
increasing response times.12 Drivers can pull into bicycle
lanes to move out of the way, and a center-turn lane can
be used by responders needing to pass other vehicles.13
“People don’t like road diets.”
The Electric Avenue road diet in Lewistown, Pa., was
opposed by 95 percent of residents when it was first
proposed; after completion, nearly 95 percent of residents
are supportive of the changes.14
1. Federal Highway Administration, Proven Safety Countermeasures. Retrieved March 4, 2014, http://safety.fhwa.dot.gov/provencountermeasures/fhwa_sa_12_013.
pdf
2. Safe Routes to School National Center (November 2013), “Safe Routes to School Online Guide.” http://guide.saferoutesinfo.org/engineering/tools_to_reduce_
crossing_distances_for_pedestrians.cfm#diet
3. Tan, C.H. Federal Highway Administration, FHWA-HRT-11-006. Vol. 75, No. 2. (September/October 2011), “Going on a Road Diet.” Public Roads, http://www.fhwa.dot.
gov/publications/publicroads/11septoct/05.cfm
4. Burden, D., Lagerway, P., Walkable Communities, Inc. (March 1999), Road Diets: Fixing the Big Roads, http://www.walkable.org/assets/downloads/roaddiets.pdf
5. Tan, C.H. Federal Highway Administration, FHWA-HRT-11-006, Vol. 75, No. 2 (September/October 2011), “Going on a Road Diet”. Public Roads. http://www.fhwa.dot.
gov/publications/publicroads/11septoct/05.cfm
6. Burden, D., Lagerway, P., Walkable Communities, Inc. (March 1999), Road Diets: Fixing the Big Roads. http://www.walkable.org/assets/downloads/roaddiets.pdf
7. Highway Safety Information System (August 2010), Evaluation of Lane Reduction “Road Diet” Measures on Crashes, http://www.fhwa.dot.gov/publications/research/
safety/10053/10053.pdf
8. Federal Highway Administration, Proven Safety Countermeasures. Retrieved March 4, 2014 from http://safety.fhwa.dot.gov/provencountermeasures/fhwa_
sa_12_013.pdf
9. Smith, G. et al. Knoxville Regional Transportation Planning Organization (July 2009), Complete Streets Design Guidelines, http://www.knoxtrans.org/plans/
complete_streets/guidelines.pdf
10. Krag, T. Aalborg University, Denmark, paper (2002), Commerce and Bicycles
11. Tan, C.H. Federal Highway Administration, FHWA-HRT-11-006. Vol. 75, No. 2. (September/October 2011), “Going on a Road Diet”. Public Roads, http://www.fhwa.dot.
gov/publications/publicroads/11septoct/05.cfm
How To Get It Right
When advocating and planning for road diets,
try the following:
Engage the public
Since road diets are a new concept in many communities,
it’s important to Involve the public as soon as possible
during the discussions and planning. Doing so can
minimize any anxiety about the unknowns and give
residents ownership of the road diet goals.
Embrace a public process and build support
Develop an education and awareness campaign prior to
implementation, and reach out broadly to community
members, elected officials and municipal leaders.
Government officials may need to see public support
before acting.
Toward that end, advocates can share this fact sheet,
talk to neighbors, build community support and then
meet with decision makers, the media, experts and others
to discuss the benefits of road diets. Agency staff can
engage the public by hosting workshops to build public
acceptance and understanding.
Start with a pilot project
Consider launching a pilot road diet in an area that
has light traffic. This will give drivers a chance to get
comfortable with the concept and allow municipal staff to
document what works and what doesn’t.
Target areas that are ripe for reinvestment
Locate a pilot project on a road that carries no more than
15,000 vehicles a day and that ideally serves a downtown
neighborhood or historic district with potential for
reinvestment and/or economic development.
Document the change
Before, during and after the road diet project is built,
observe and record what’s happening. The information
can make it easier to conduct future road diets at higher
traffic counts. In addition to traffic flow monitoring,
document any increases in walking, bicycling, transit use
and retail activity.
Utilize clear signage
During and even after completing a road diet project
continue to use signage and markings to highlight and
explain any features that might be unfamiliar.
Design it well
There is no one-size-fits-all design for a road diet. Make
sure what you create fits the traffic volume, the road’s
physical location and the community’s shared goals.
This four-lane road in Redondo Beach, Calif., is not
pedestrian or bicycle friendly and the road’s traffic
volumes doesn’t justify having four vehicle lanes.
A transformation like the one illustrated here
increases safety, parking, pedestrian and bicyclist
access and creates a people-friendly sense of place.
12. Rosales, J. Parsons Brinckerhoff (July 2009), Road Diet Handbook: Setting Trends for Livable Streets, http://www.ite.org/emodules/scriptcontent/Orders/
ProductDetail.cfm?pc=LP-670; and Walkable Streets (August 2003), Economic Merits of Road Diets and Traffic Calming, http://walkablestreets.wordpress.
com/2003/08/17/economic-merits-of-road-diets-and-traffic-calming/
13. Qlkable Streets (August 2003), Economic Merits of Road Diets and Traffic Calming, http://walkablestreets.wordpress.com/2003/08/17/economic-merits-of-road-
diets-and-traffic-calming
14. Burden, D., Lagerway, P., Walkable Communities, Inc. (March 1999), Road Diets: Fixing the Big Roads. http://www.walkable.org/assets/downloads/roaddiets.pdf
Success Stories
Orlando, Florida: Edgewater Drive
A 1.5-mile section of Edgewater Drive was put on a road
diet in 2000, converting four lanes to two.
The results: 34 percent fewer crashes and 68 percent
fewer injuries. Speeds decreased by up to 10 percent.
Property values increased 8 to 10 percent in residential
areas and 1 to 2 percent for commercial areas. Travel times
through the corridor sped up by 25 seconds even with an
increase in traffic volume. There was a nearly 40 percent
increase of on-street parking, and walking and bicycling
rates rose by 56 and 48 percent, respectively.
Seattle, Washington: Stone Way North
In 2008, a road diet was completed on a 1.2-mile section of
Seattle’s Stone Way North. The four-lane roadway carrying
13,000 vehicles per day was turned into a two-lane
roadway with a center-turn lane, bicycle lanes and parking
on both sides. Speeds on the road decreased, but drivers
did not divert to other areas in search of alternate routes.
Two years of crash data showed an overall decrease
of 14 percent, injury crashes dropped by 33 percent and
angle crashes dropped by 56 percent. Bicycle volume
increased 35 percent (to almost 15 percent of the peak
hour traffic volume), yet the bicycle collision rate showed
no increase. Pedestrian collisions decreased 80 percent.
Athens, Georgia: Baxter Street
A road diet conversion on an arterial with 20,000 vehicles
daily resulted in crashes dropping 53 percent in general
and 60 percent at unsignalized locations. Traffic diversion
was less than 4 percent, and 47 percent of the road’s users
perceived the number of lanes and street width as being
“just right.” (One-third were unsure and 20 percent were
unhappy.) Baxter Street was converted from four lanes to
two with a center lane and bicycle lanes on both sides.
hoW IT WorkS
The most common type of road diet converts four lanes of
traffic into three lanes consisting of two travel lanes and a
center left-turn lane. The configuration opens up space for
adding such features as bicycle lanes, on-street parking,
pedestrian buffers and sidewalks.
BEFORE: This roadway is designed primarily for motor
vehicles. Wide, multiple travel lanes encourage faster
speeds. The likelihood of drivers making lane changes
increases the risk of crashes.
AFTER: A road diet opens up space for bike lanes, wider
sidewalks, landscaping and pedestrian-scale lighting, all
of which increase a community’s ability to attract new
development along the roadway. Narrower, single travel
lanes encourage moderate and slower speeds that reduce
crash risks.
AArP LIVABLE CoMMUNITIES
Mail: 601 E Street NW, Washington, DC 20049
Email: livable@aarp.org
Online: aarp.org/livable
WALkABLE ANd LIVABLE CoMMUNITIES INSTITUTE
Mail: 2023 E. Sims Way #121, Port Townsend, WA 98368
Email: community@walklive.org
Online: walklive.org
1. Los Angeles County Model design Manual for Living Streets. (2011)
http://www.modelstreetdesignmanual.com/
2. road diet handbook: Setting Trends for Livable Streets. Available for
purchase from Institute for Transportation Engineers, http://bit.ly/RCo4sw
3. “rightsizing Streets.” Project for Public Spaces, http://www.pps.org/
reference/rightsizing/
4. The Safety and operational Effects of road diet Conversion in
Minnesota. http://www.cmfclearinghouse.org/study_detail.cfm?stid=68
5. Proven Safety Countermeasures. http://safety.fhwa.dot.gov/
provencountermeasures/fhwa_sa_12_013.pdf
6. Evaluation of Lane reduction “road diet” Measures on Crashes.
Highway Safety Information System, http://www.fhwa.dot.gov/publications/
research/safety/10053/10053.pdf
7. “Moving Beyond the Automobile.” Streetfilms, road diet video featuring
Dan Burden on Vimeo: http://vimeo.com/21903160
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