Featured Research: Developing a Methodology to Evaluate Detours for Major Construction Projects in the Era of Real-Time Route Guidance

An example of static signage used by managing agencies for communicating a detour to the public.

During major road construction projects, when certain lanes or roads are closed, managing agencies are responsible for designating detour routes and communicating them to the public. They do this in a variety of ways using static signage, variable message signs (VMS), highway advisory radio, project websites, and television and radio.

But what is not known is how the detour information is being used by motorists, how they choose their routes around road construction projects, where they are getting their information, and how effective the different strategies are.

STRIDE researchers Andrew Sullivan, MSCE, and Dr. Virginia Sisiopiku of the University of Alabama at Birmingham have set out to tackle these questions and are working on creating a methodology for detour route planning that will include a set of best practices for long-term construction projects. The inspiration for this project was the reconstruction of I-20/59 through downtown Birmingham in 2019.

Andrew Sullivan, UAB

“A 1.5-mile segment of interstate that carries 160,000 vehicles per day was closed for one year, so the impacts were regional,” Sullivan said. “Local agencies put out a lot of information about detour routes, but it wasn’t clear how that information was being used. We want to better understand how motorists make detour decisions in this era of in-vehicle route guidance and multiple information sources.”

To do this, they are using the I-20/59 project as a case study, evaluating the planning and communication strategies used by the Alabama Department of Transportation and City of Birmingham to inform the public of available detour routes, and comparing those to the actual detour choices made by motorists. The study will include a survey of motorists to determine what sources of information they used to make detour decisions and how they prefer to receive such information in the future.

Sullivan believes the results will be applicable in a wide range of environments. It will provide guidance to managing agencies about the most effective ways to communicate detour information to motorists.

“As an example, we are already seeing that strategies used for commercial vehicles may need to be different than those used for private motorists,” he said. “The goal is to help managing agencies allocate their limited resources as efficiently as they can.”