The Pedestrian and Bicycle Information Center (PBIC) has produced a report that reviews and synthesizes research on the effectiveness of road diets in improving safety.  The report, "Road Diet Conversions: A Synthesis of Safety Research," assesses the available evidence regarding the safety benefits of reducing the number of motorized traffic lanes, commonly referred to as road diets. Road diets have been used since the 1970s, but little work has been done to evaluate how much the lane reductions improve safety.  The report examines six controlled safety evaluation studies conducted between 2002-2013.

Road diets are one of nine proven safety countermeasures promoted by the Federal Highway Administration's (FHWA) Office of Safety. For more information on road diets as a safety countermeasure, visit the FHWA website.