Michigan Department of Transportation (MDOT) teamed up with Federal Highway Administration (FHWA) and Michigan State University for an 18-month study to test the use of variable speed limits (VSL) in work zones. The Michigan study is part of a larger FHWA-sponsored variable speed limit pilot program.

MDOT opted to lease equipment through a contract that included development, design, installation, calibration, and maintenance over six months for $400,900. By leasing the equipment, MDOT did not need to maintain or store the equipment after construction ended.

The VSL system, which was deployed along I-96 in Lansing, consisted of seven trailers with remote traffic microwave sensors, solar power, controllers with radio frequency communication, and light-emitting diode (LED) speed displays. Work zone speed limits were based on traffic congestion, weather, presence of workers, and other factors.

See Also:
Variable Speed Limit System: Development, Demonstration, and Evaluation at http://www.egr.msu.edu/cee/research/transportation/PROJ_VSL.shtml and Michigan Department of Transportation and Michigan State University, Field Test of Variable Speed Limits in Work Zones (In Michigan), Final Report, September 2003 at http://tig.transportation.org/sites/aashtotig/docs/VSL%20Entire%20Final%20Report.pdf.

Notes:
Click here for pictures of the VSL system in Michigan (81 KB).