You are here

Improving Signing and Markings at Complex Interchanges

Project Information

Project ID: 
Project Status: 
Start Date: 
Wednesday, September 1, 2010
End Date: 
Thursday, September 13, 2012
FHWA Program: 
FHWA Subprogram: 
Safety Data and Analysis, Manual on Uniform Traffic Control Devices (MUTCD)
FHWA Topics: 
Road Operations and Congestion--Manual on Uniform Traffic Control Devices (MUTCD)
TRT Terms: 
Safety; Interchanges; Research; Signs; Human Factors; Road Markings; Design
FHWA Discipline: 
Design, Operations, Safety
TRB Subject Area: 
Highways, Research, Safety and Human Factors, Design

Contact Information

First Name: 
Last Name: 
(202) 493-3990
Email Address: 
Human Factors Team
Office of Safety Research and Development
Office Code: 

Project Details

Project Description: 

The objective of the project is to identify potential improvements to current marking and signing practices for complex interchanges.


The key project objective is to identify potential improvements to current marking and signing practices for complex interchanges. A human factors study will be conducted to examine these alternative signing and marking treatments to determine their effects on driver decisionmaking, comfort, and safety. 

Partners and Other Sponsor/Managing/Performing Organizations: 


Deliverable Name: 
Enhancing Safety and Operations at Complex Interchanges With Improved Signing, Markings, and Integrated Geometry
Deliverable Type: 
Research report or guidelines
Deliverable Description: 
The National Highway System has experienced rapid growth in demand that has far outpaced the increase in new capacity. Roadway designers are turning toward additional lanes, preferential lanes and ramps, and multilane exits in their interchange designs to address the continued mobility demands. While these mobility and capacity enhancements address the challenge of increased demand, they also complicate the design and operation of interchanges. Drivers approaching these complex interchanges are required to perform several navigation tasks that are often short in both distance and time. The purpose of this study was to develop recommendations for signing, delineation, and geometric design that will reduce workloads at critical points approaching complex interchanges. In doing so, this project identified many attributes that contribute to complexity; evaluated multiple interchanges across the United States for their design, signing, and marking practices; conducted a series of driving simulator studies; and observed and analyzed video investigating real-world driving behaviors at complex interchanges. Each key finding and recommendation is provided in the report, along with examples that explain the involved principles and suggested guidelines for implementation. This report should be useful to transportation professionals, State transportation departments, and researchers interested in developing complex interchange designs that consider driver behavior more effectively.