InTrans / Mar 15, 2021

Road Diets: An Overview & Opportunities to STEP UP

In 2019, as an effort to improve pedestrian safety, the Federal Highway Administration (FHWA) introduced the STEP or Safe Transportation for Every Pedestrian program—an Every Day Counts initiative.

For pedestrian safety, one of the countermeasures promoted in STEP is road diets, which can reduce vehicle speeds and the number of lanes pedestrians cross. Road diets can also sometimes create space to add new pedestrian facilities such as refuge islands.

The benefits of the STEP program include improved safety through countermeasure implementation, targeted investment on pedestrian safety, and enhanced quality of life for pedestrians. STEP identifies and describes a number of effective countermeasures, such as raised crosswalks, pedestrian hybrid beacons, etc.; however, the FHWA emphasizes that each should be used in the appropriate roadway context.

The impacts, feasibility, design, and effectiveness evaluation of road diets were described in the FHWA Road Diet Informational Guide.

Although seven years old now—having been published in 2014—this guide is still the FHWA’s go-to resource on the subject.

Iowa Local Technical Assistance Program (LTAP) Director Keith Knapp co-authored the original four- to three-lane conversion guidelines for Iowa and is also a co-author of the 2014 Road Diet Informational Guide. He has been involved with road diets for over 20 years.

“Some people think [Road Diets] are negative because of the term ‘diet.’ They don’t like that it implies making the roadways ‘skinnier.’ Instead, I like to think about it like this: lane reallocation, lane rebalancing, and conversion.”

Knapp adds that when considering a road diet, each potential location should be context sensitive.

“Ask yourself: Will this serve everyone? Why am I doing this?”

In many cases, road diets have been known to reduce conflict points, improve sight lines, lower or create more uniform speeds while still meeting traffic demands, provide opportunities for “green” features, as well as lower costs while still supporting traffic flow (vehicles, bicycles, and pedestrians) for area businesses.

It is not unusual for a four-lane undivided highway to have a history of increasing crashes as traffic volumes rise and more and more motorists begin to share the inside lane for through movements and left turns. According to the guide, with the use of a road diet, conversions could result in an overall crash reduction of 19 to 47 percent.

Additionally, as active transportation increases, communities desire more livable spaces, pedestrian and bicycle facilities, and transit options, which may not be easily and/or safely accommodated along a four-lane undivided roadway.

“Everything depends on the situation you are looking at, always remember to get feedback and get people involved early,” says Knapp.

There are six chapters that make up the Road Diet Information Guide, including information on road diet feasibility, design, and effectiveness. The guide can be downloaded or viewed here.

Additionally, 24 case studies from 9 states have been conducted to show the outward benefits of road diets. These can be viewed here.

More Information

In October 2020, Knapp led a webinar focusing on Road Diets and provided an overview of the Road Diet Informational Guide. A link to the recording can be found here. Tune in for more webinars on important safety and transportation-related topics here.

More information about the STEP program can be found here and here.