Cooperative Intersection Collision Avoidance System -- Stop Sign Assist: Experiments to Validate Use of an In-Vehicle Interface Design
Report no. CTS 12-09
The three studies included in the current report examine the transition from an infrastructure-based rural
intersection crossing assist system to one located inside a vehicle. The primary goals of the first study, conducted in
a simulator, were to examine the effect of potentially confounding factors, such as the drivers' familiarity with the
assist system and the impact of cognitive load on the drivers' performance. Next, we examined the efficacy of
several different designs of such system to determine the optimal interface design to be used for the in-vehicle
system. Finally, the optimal design of the system was examined in the third study, as a field test. The results
showed that the use of the system under cognitively demanding conditions did not result in any adverse
consequences, which suggested that the processing of the system required minimal cognitive resources.
Additionally, the results showed that the benefits of the assist system, such as reduced probability of accepting a
critical gap were exhibited under the limited visibility conditions when the perceptual task of determining an
appropriate crossing gap became overly demanding. The results from the field study showed that the use of the
assist system resulted in improved intersection crossing performance exhibited in increased likelihood of making a
complete stop at the stop sign and showed a strong trend toward a decreased probability of accepting critical gaps.
Additionally, the impact of the in-vehicle CICAS-SSA was equivalent for older and younger drivers; that is, both
age groups benefited from the use of the system.
Sponsored by: Minnesota Department of Transportation