The CICAS-SSA sign is a roadside driver support system that is intended to improve gap rejection at rural stopcontrolled
intersections. The CICAS-SSA system tracks vehicle locations on a major roadway and then displays
a message to a driver on the minor road via an active LED icon-based sign. The basis of this sign is a “Divided
Highway” sign that is commonly presented in traffic environments. Overlaid on the roadways of the sign are
yellow or red icons that represent approaching vehicles that are at a distance at which the driver on the minor
road should proceed with caution or at a distance that is considered unsafe to enter the intersection.
Previous research conducted in a driving simulation environment indicated potentially beneficial changes in
driver decision-making relative to approaching vehicle gap sizes and indicated that drivers perceive the system as
being both useful and satisfying. While simulation-based evaluations provide a wealth of useful information,
their ability to replicate the full array of behavioral, cognitive, and perceptual elements of a driving environment
do have some limitations. It is because of these limitations that it is useful to confirm simulation-based findings
in a real-world environment.
The primary goal of the current work was to evaluate the candidate CICAS-SSA sign in a real-world setting to
confirm previously identified benefits and identify any unintended consequences of sign usage. This goal was
accomplished through a validation field test performed at the intersection of US Highway 52 and County Road 9
in Southern Minnesota. The findings of the work are summarized in this report.
Rakauskas, Michael; Creaser, Janet; Manser, Michael; Graving, Justin; Donath, Max.
Validation Study – On-Road Evaluation of the Cooperative Intersection Collision Avoidance System – Stop Sign Assist Sign: CICAS-SSA Report #5.
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