U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Road Diets are an innovative roadway reconfiguration that improves safety, increases livability, and can advance the area's economic growth. Even after hundreds of successfully implemented Road Diets across the country, many misconceptions still arise. This flyer debunks some of the most common Road Diet myths.
This is false. A Road Diet can drastically improve a corridor's quality of life and the appeal or "livability" of an area. Livability is a term used to describe the tie between the quality and location of transportation facilities to broader opportunities such as access to jobs, affordable housing, and safer streets, which all promote economic development. For the majority of Road Diets, the Average Daily Traffic (ADT) remains constant; however, some Road Diets have seen a decrease in vehicular traffic and an increase in bicycle or pedestrian traffic. The Seventh Street Road Diet in Los Angeles, California saw bicycle traffic double as the result of the bicycle facilities provided by the Road Diet.
This is false. Road Diets typically do not adversely affect travel times within a corridor; rather, clearing clogged travel lanes of left-turning traffic actually improves operations.
For example, when a corridor has numerous access points (driveways), the majority of through traffic tends to utilize the outside travel lanes to avoid being delayed by left-turning vehicles slowing and stopping in the inside travel lanes. These four-lane corridors essentially behave like a three-lane road (see left figure). As such, when these four-lane corridors are converted to a three-lane section, they are unlikely to increase congestion.
This is false. Many Road Diets do not narrow existing lanes while others may only narrow lanes slightly. In all cases, engineers ensure that lanes are still wide enough to accommodate large vehicles like freight trucks, school buses, and transit buses. In fact, Road Diets present an opportunity to re-plan the roadway space for large vehicles by including delivery parking areas, improved intersection turning radii, and protected bus pullouts for pickup or drop-off. Road Diets can also incorporate wider shoulders, which increase the space between pedestrians and large vehicles.
This is false. Road Diets can improve emergency response times. Multi-lane undivided roads can be awkward and unsafe for emergency responders, and can slow response times. Drivers are often uncertain about where to go to allow emergency responders to pass.
If the outside travel lane has traffic, inside-lane drivers cannot pull over until they see where space remains. Sometimes inside-lane drivers move over only slightly and stop. Emergency vehicle drivers may thread a path somewhere along the center of the roadway if they are able to move at all ("Before" side of the figure).
A two-way left-turn lane and wide shoulder areas allow traffic to move aside more quickly. The center turn-lane provides a predictable path for the emergency response vehicle ("After" side of the figure). Left-turning vehicles in the center lane often have the ability to clear the way, by either executing their left-turn or by moving to the right, when other vehicles have stopped. Additional "free space" provided by Road Diets in the form of wider shoulders, bicycle lanes, or parking can also accommodate vehicles yielding to emergency response vehicles.
A Road Diet's primary objective is to improve safety for all roadway users, while increasing livability by creating a bicycle- and pedestrian-friendly environment. This in turn can encourage economic growth by increasing property values and attracting businesses. Road Diets are an opportunity to redesign and reallocate roadway space to better meet the needs of all users and can be tailored to reflect the individual needs and desires of the communities in which they are implemented.