Treatment Tuesday: Road Diets

Photo Credit: Michael Ronkin

Photo Caption: The photos above depict a typical road diet. In the top photo you see a four lane road with two lanes in each direction. In the second photo one lane is removed, another is converted to a turn lane, and the remaining space is converted to bike lanes in each direction. In the third photo, important finishing touches are added to enhance safety: a high visibility crosswalk, a median island, a stop bar for cars approaching the crosswalk, and signage.


If a good friend asked you for advice on losing weight, you probably wouldn't tell them to buy a larger belt. A larger belt wouldn't address the root of the problem. Instead, you may tell your friend to take a closer look at his or her diet and make some changes.

More and more transportation planners and traffic engineers are beginning to apply this "diet" concept to how we manage car congestion on our roads. Because latent demand for road space eats away at the benefits of added roadway, they know we cannot build our way out of congestion. Instead of building more roadway they are implementing road diets that balance out the transportation options available and the efficiency of travel flow. A road diet often consists of adding a center turn lane and bicycle and pedestrian facilities as shown in the above picture.

There are streets in St. Louis that look like the street above--four lanes or more with little traffic. Streets with less than 20,000 auto trips per day are often great candidate streets for road diets. Streets downtown appear to have tons of possibility--streets like Delmar, Olive, and Market. Check out St. Louis Urban Workshop's St. Louis Streets are Morbidly Obese blog post for another perspective.

Road diets could be a great tool for St. Louis as we try to encourage active lifestyles. Because they can create more space for pedestrians and cyclists and slow car traffic, they create safe and pleasant environments for walking and biking. Additionally, because road diets maximize road efficiency, using them more often can lead to road construction savings and air quality benefits.

Read Road Diets: Fixing the Big Roads to learn more. (Click on Road Diets on this page.)