SAFE TRANSPORTATION Road Diet FOR EVERY PEDESTRIAN 

COUNTERMEASURE TECH SHEET 

June 2018, Updated | FHWA-SA-18-066
 

Road Diet 

EDC-4 STEP: https://www.fhwa.dot.gov/innovation/everydaycounts/edc_4/step.cfm 

A typical Road Diet converts an existing 

four-lane, undivided roadway to two 

through lanes and a center, two-way left 

turn lane. This design allows left-turning 

drivers to exit the traffc stream while waiting 

for a gap to complete their turn and frees 

up space that can be reallocated to other 

uses, including: 

» Pedestrian refuge island 

» Crosswalk visibility enhancements, such

as curb extensions 

» On-street parking, with parking restrictions

on crosswalk approaches 

» Widened sidewalks and landscaped

buffers 

» Bicycle lane and/or transit lanes 

A Road Diet can be a relatively low-cost 

safety solution, particularly where only 

pavement marking modifcations are 

required to implement the reconfgured 

roadway design. When planning in 

conjunction with reconstruction or overlay 

projects, the change in cross section may 

be completed without any additional cost. 

CONSIDERATIONS 

While Road Diets are effective 

countermeasures for midblock collisions, 

they are not recommended for all multilane 

roadways. Typically, a suitable roadway has a 

current and future average daily traffc (ADT) 

equal to or less than about 20,000. In some 

instances, Road Diets have been successfully 

used on roads with ADTs as high as 25,000. 

FHWA’s Road Diet Informational Guide 

provides a closer look at the safety and 

operational benefts of Road Diets to help 

agencies determine if this countermeasure 

may suit their needs. Communities will need 

to consider a range of factors, including: 

» Vehicle speed 

» Level of Service (LOS) 

» Quality of Service 

» Vehicle volume (ADT) 

» The operation and volume of pedestrians, 

bicyclists, transit, and freight 

» Peak hour and peak direction traffc fow 

» Vehicle turning volumes and patterns 

» Frequency of stopping and slow moving 

vehicles 

» Presence of parallel roadways 

Since Road Diets may be new or uncommon 

in a community, consider conducting an 

outreach effort to educate the public on the 

purpose and potential benefts. 

COST 

The cost associated with a Road Diet can 

vary widely. Restriping costs for the three 

lanes plus bicycle lanes are estimated at 

$25,000 to $40,000 per mile, depending 

on the amount of lane lines that need to 

be repainted. When a Road Diet involves 

geometric features like extended sidewalks, 

curb extensions, a raised median or refuge 

island, the costs can increase to $100,000 or 

more per mile. 

References 

Pawlovich, M.D., W. Li, A. Carriquiry, and T. Welch. "Iowa's Experience with Road Diet Measures—Use of Bayesian Approach to Assess Impacts on Crash Frequencies and Crash 

Rates." Transportation Research Record: Journal of the Transportation Research Board, No. 1953, Transportation Research Board, Washington, D.C., 2006. 

Persaud, B., B. Lan, C. Lyon, and R. Bhim. "Comparison of empirical Bayes and full Bayes approaches for before–after road safety evaluations." Accident Analysis & Prevention, 

Volume 42, Issue 1, 2010, pp. 38-43. 

Knapp, K., B. Chandler, J. Atkinson, T. Welch, H. Rigdon, R. Retting, S. Meekins, E. Widstrand, and R.J. Porter. (2014). Road Diet Informational Guide. FHWA-SA-14-028, Federal 

Highway Administration Offce of Safety, Washington, D.C. Available: https://safety.fhwa.dot.gov/road_diets/guidance/info_guide/form.cfm 

Federal Highway Administration. (2013). “Lane Reduction (Road Diet)” in PEDSAFE: Pedestrian Safety Guide and Countermeasure Selection System. Available: http://www. 

pedbikesafe.org/PEDSAFE/countermeasures_detail.cfm?CM_NUM=19