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Center for Transportation Studies

Programs & Labs

Cooperative Intersection Collision Avoidance System—Stop Sign Assist (CICAS-SSA)

Researchers from the ITS Institute’s Intelligent Vehicles Laboratory (IV Lab) and HumanFIRST Program, in cooperation with the Minnesota Department of Transportation (MnDOT), have developed an infrastructure-based driver-assist system designed to help drivers make better decisions and prevent collisions at rural highway intersections.

The Cooperative Intersection Collision Avoidance System–Stop Sign Assist (CICAS–SSA) system uses multiple sensors and advanced computer algorithms to track vehicles moving along a rural divided highway. This information is used to warn drivers stopped on a secondary rural road when gaps in highway traffic are too small to merge or cross safely; an active LED icon-based sign switches to an alert or warning as needed depending on the gaps to the left or right.

System field-testing of CICAS-SSA began in 2010 at the intersection of U.S. Highway 52 and County State Aid Highway (CSAH) 9 near Cannon Falls, Minnesota, and at the intersection of U.S. 53 and Wisconsin Highway 77 south of Spooner, Wisconsin. These intersections were chosen because of their history of serious crashes and fatalities for which unsafe gap acceptance was a key contributing factor.

Two more test systems were activated in Minnesota in June 2011: the first on Minnesota Highway 23 at CSAH 7 near Marshall and the second on U.S. Highway 169 at CSAH 11 near Milaca. Between 2006 and 2008, an average of four right-angle crashes per year occurred at each of these intersections.

Testing at the selected intersections is planned to run for three years. Researchers are using data collected at these locations to analyze driver responses in relation to the system’s sign modes and to determine whether the CICAS-SSA system improves the gap acceptance of drivers. If drivers learn better behavior, crash rates should drop for all intersections, not just those at which the CICAS-SSA system is deployed.

CICAS-SSA Demonstration Video

This video shows the view from inside a vehicle as it passes through the CICAS-equipped intersection of U.S. Highway 52 and CSAH 9.

Goodhue County Intersection Cameras

These live cameras overlook the U.S. Highway 52 and CSAH 9 intersection in Goodhue County. 

Camera 1 - Facing East
Camera 1 - Facing East
Camera 2 - Facing West
Camera 2 - Facing West