Background and Objectives

More than 50 percent of the combined total of fatal and injury crashes occur at or near intersections. The Federal Highway Administration’s (FHWA’s) intersection safety and design research facilitates the implementation of short-term safety improvements, and defines and evaluates long-term, higher payoff strategies to improve intersection safety.

Intersection safety and design research has led to the development and successful deployment of innovative intersection and interchange designs, including the modern roundabout, mini-roundabout, continuous flow intersections, restricted crossing U-turn intersections, and diverging diamond interchanges. Our current field studies include investigating the causation factors of traffic crashes at multilane roundabouts, evaluating different forms of protected intersection designs aimed at facilitating the safe movement of pedestrians and bicyclists at large intersections, and modular miniroundabouts made of recycled plastics for civilian, military, and disaster relief applications.

We performed analyses on multiple big datasets to explore driver behaviors at different types of intersections, and develop big data analytics and visualization tools that can identify high-crash locations, detect traffic incidents, and assess the societal impacts of traffic crashes. New studies are  underway to understand driver visual searching behaviors at alternative intersections/interchanges;, explore concepts of tandem and corridor applications of different forms of alternative intersection designs; applications of edge computing for real time detection of all road users and real time decision making to improve safety at signal controlled intersections.

FHWA will identify the most common and severe problems and compile information on the applications and design of innovative safety countermeasures at interchanges and both signalized and non-signalized intersections. New explorations aim to reveal strategic operational and research opportunities to further intersection safety.

Publications and Downloads

Download: Federal Highway Administration (FHWA) Interchange Safety Comparison Tool

Abstract: This spreadsheet tool was developed through the FHWA research project, Safety Comparison Between Interchange Types. This tool implements the crash prediction models (developed under this study) for diamond, compressed diamond, roundabout diamond, diverging diamond, single-point diamond, tight diamond, and partial cloverleaf (parclo) interchanges. The interchange types included in this study represent the top 70 percent of the interchange types used by the State Departments of Transportation. This tool is intended for use at the planning stage to help assess the safety performance of the commonly used interchange types.

User manual: FHWA Interchange Safety Comparison Tool
Interchange Comparison Safety Tool User Guide | FHWA (dot.gov)

TechBrief: Safety Comparison Between Interchange Types
https://highways.dot.gov/research/publications/safety/FHWA-HRT-23-029