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Run-off-road (ROR) crashes are a concern for two-lane rural and urban roadways throughout Minnesota due to the frequency by which they contribute to fatal crashes (Minnesota Crash Facts, 2013). Mitigating the severity of the ROR events is an on-going research goal in order to help reduce the number of ROR crashes. Examining countermeasures that may reduce ROR crashes is important to determine the most efficient and effective method of warning. Behavioral responses were examined through the use of an in-vehicle haptic-based lane departure warning system (LDWS) using a driving simulator. The study incorporated systematic variation to both the reliability of the warning and sequence of treatment conditions. An additional analysis examined the presence of behavioral adaptation after repeated exposure to the system. Severity of a ROR event was measured as the total time out of lane (TTL) and maximum lane deviation (MLD). Covariates (e.g. road shape) were examined to determine the influence they may have on the severity of a ROR. The results reveal overall LDWS efficacy. TTL was significantly longer when no system was active compared to when it was active. LDWS led to shorter duration of ROR events. Greater velocity was found to be highly predictive of longer TTL. MLD was also greater for baseline drives compared to treatment drives. No behavioral adaptation or system overreliance was detected, suggesting long term benefits of the LDWS. Drivers who actively engaged in a distraction task were at far greater risk of traveling greater and more dangerous distances out of lane.

Each year, there are over 500 fatal crashes in work zones in the U.S., with over 100 road construction workers killed on work sites (NSC, 2011; FARS, 2011). Speed and distraction are among the top contributing factors to work zone crashes (Garber & Zhao, 2002; Mountain, Hirst, & Maher, 2005; Wilson, Willis, Hendrikz, Le Brocque, & Bellamy, 2006). The purpose of this study was to investigate the impact of different types of speed enforcement methods on driver attention in work zones. The investigation not only examined enforcement methods currently used in Minnesota, but also examined how implementing automated speed enforcement (ASE), which is not currently used in Minnesota, may influence driver attention and behavior in simulated work zones. Overall, the results do not appear to support the hypothesis that ASE without dynamic speed display sign (DSDS) improves driver attention in work zones. There is some evidence, however, that drivers did heighten their visual attention in work zones with ASE+DSDS enforcement. Drivers fixated on the secondary task display less frequently in the ASE+DSDS condition compared to other enforcement types while they traveled in the downstream portion of the work zone. The largest effects of the study were found among the age groups, with younger and older drivers exceeding the speed limit most often and varying their speed slightly depending on the type of enforcement present. Middle-aged drivers exhibited the greatest speed control and tended to abide by the speed limit to the same extent regardless of the type of enforcement present.