Driver Responses to the AWARE Intrusion Alarm System

This study was conducted to assess how motorists approaching a simulated work zone with an AWARE alarm system would respond if the alarms are activated (and understand why they responded as they did), as compared to their reaction to an identical simulated work zone without an AWARE alarm activation. A demographically-balanced group of 63 drivers from the Bryan-College Station, Texas area were recruited to drive an instrumented vehicle around a test course created at the Texas A&M University Riverside Campus. During the traversal of the test course, study participants passed by two simulated shoulder work zones, the second of which included the AWARE alarm system that was activated for approximately three to four seconds as the participant approached and passed the work zone.  Data were recorded regarding vehicle speed, amount of accelerator depression, amount of brake depression, and steering wheel angle at 10 hertz through a 450 foot segment approaching and passing by both work zones.  Changes in each of the variables over that segment at each work zone were compared to determine if the AWARE alarm resulted in more dramatic responses by drivers, and whether those responses might adversely affect safety if occurring at real work zones. Participants were asked a series of questions at the end of the driving portion of the study to understand their thoughts about what the alarm meant and what a driver should do in response to the alarm.

Overall, very few statistically significant changes in behavior were detected in driver reactions to the AWARE alarm system relative to their reactions to an identical work zone where an AWARE alarm system was not present. On average, changes in speed approaching and passing by the work zones, changes in accelerator and brake depression levels, and steering wheel rotations were statistically similar when passing by both work zones, and indicated that the AWARE alarm activated at the second work zone did not have an adverse effect on driver behavior.

During the course of the studies, study administrators observed approximately 15 percent of the participants that appeared somewhat surprised by the activation of the AWARE alarm system, compared to the other 85 percent who did not display any outward reaction to the alarm when it was activated.  Participant responses to the questions administered at the conclusion of the driving task indicated a common perception that the alarm was initiated to get them to slow down, which is one of the desired outcomes of the system. However, study administrators also found that many of the participants perceived the AWARE alarm as a police or emergency vehicle presence nearby.  Furthermore, 50 percent of the participants who viewed the red/amber warning lights in combination with the audible alarm believed that they should have pulled over and stopped, which would be a proper response to a police or emergency vehicle. A somewhat smaller percentage (28 percent) who viewed the white flashing lights believed this would have been the proper response as well.  It should be noted that none of the participants actually made this maneuver during the test, though.

Based on these findings, the researchers recommend utilizing the white flashing lights rather than red/amber lights on the AWARE alarm. Also, researchers recommend that the audible alarm component in the AWARE system be modified to better differentiate it from the sirens that are typically associated with police and emergency response vehicles. Specifically, changing the alarm to consist of short bursts (perhaps less than one second long), similar to how back-up alarms on construction equipment operate, may better ensure that approaching motorists do not misinterpret the alarm as an emergency vehicle siren.