Effectiveness of Animal Advisory Messages on Dynamic Message Signs as a Speed Reduction Tool

Abstract

Animal–vehicle collisions (AVCs) are a growing concern as the number of vehicle miles traveled and human encroachment into wildlife habitat increase throughout the United States. Measures to prevent AVCs, such as fencing and wildlife passages, can impose significant investments for transportation agencies. An alternative and potentially less expensive approach is the use of signs to modify driver behavior to reduce these collisions. This study investigated the effectiveness of seasonal animal movement advisories as a speed reduction tool on Interstate highways. Two permanent and one portable dynamic message signs (DMSs) were used to post messages advising motorists to watch for wildlife moving across Interstate 90 in the Bozeman Pass region of southwestern Montana. One control and three treatment messages were displayed on the DMSs, and driver reactions to these messages were recorded through speed observations. The control message comprised a blank message; and the treatment messages included a general transportation message, one general wildlife advisory message, and another, similar wildlife advisory with an updated tally of the actual number of animals observed to have been hit on Bozeman Pass for the year. The results suggest that wildlife advisory messages posted on permanent and portable DMSs are generally effective in reducing average motorist speeds. The results also suggest that the advisory messages are more effective at reducing speeds during dark conditions. Furthermore, the messages on the portable DMS were found to have a more significant impact on average speed than the messages on the permanent DMSs.