Research Project Summary – Evaluation of Speed Activated Displays and Low Cost Treatments on Rural Curves

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February 24, 2015
Speed Signage
Speed Signage
On-pavement curve warning sign.
On-pavement curve warning sign.

Project Title: Evaluation of Speed Activated Displays and Low Cost Treatments on Rural Curves

Principal Investigator (PI): Shauna Hallmark

PI Institution: Iowa State University

PI email:

PI phone: (515) 294-5249


Sponsor:  USDOT,Iowa DOT, Iowa Highway Research Board, and the Midwest Transportation Consortium

Location:  Iowa

Project budget / award:$760,328

Project dates:  September 2007 to July 2012


This project is a national demonstration project to evaluate the effectiveness of dynamic speed signs on high crash curves on two-lane rural roadways in seven states to decrease speeds and reduce crashes. The team has installed and is monitoring signs in Texas, Washington, Florida, Arizona, Ohio, Oregon, and Iowa on high crash curve locations on two-lane rural roadways.  Low cost strategies, including adding additional reflectorized treatments to existing chevrons and on-pavement curve warning signs, were evaluated in Iowa.

Why was this project important (i.e., reason for conducting project or benefit)?  Nearly 58 percentof roadway fatalities are lane departureswith a large percentage occurring on rural two-lane roadways. Curves in general are problematic because they have three times the crash rate of tangent sections. Speed is also a major factor in fatal crashes. Consequently, focused attention on reducing speed on curves will result in improved safety.

Is this project transformational or translational in nature (or basic, advanced, or applied)?  Applied

Key outcomes from the project:  Interim report and conference paper (TRB)

Were the results of this project directly implemented and, if so, briefly how?  Project is ongoing

What mode(s) does this project address (e.g., highway, transit, rail, air, water, bike, ped)?  Highway

Is this project multi-disciplinary?  What discipline(s)?  No

Was this project conducted in collaboration with more than one institution? Yes, Texas A&M Transportation Institute (TTI) and Portland State University (PSU) partnered with Iowa State University.  

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