Determination of Traffic Control Device Selection for Nighttime Maintenance of Traffic

Each year more than 700 fatalities occur nationally due to vehicular accidents within work zones. New developments and technologies have paved the way for the creation of diamond grade sheeting, a new, more retroreflective sheeting. Research has shown that diamond grade sheeting is 6 to 14 times brighter then engineering grade sheeting and is already widely required for use on work zone signs. However, the diamond grade sheeting is not widely required for use on channelizing drums due to the increased cost and concern that the increased retroreflectivity of
the sheeting may actually decrease the safety of the work zone when used on closely spaced construction drums. A comparative parallel study was conducted to compare the safety impacts of the diamond grade sheeting with high intensity sheeting, the current MUTCD standard. Driver behavior within the work zone was analyzed in terms of lane placement and traveled speed with respect to the posted speed limit. These data were collected and analyzed to determine the extent to which the behaviors different between the two traffic control treatments. A current practices survey was also distributed to each state department of transportation to determine the extent to which diamond grade sheeting is being used. Of the 80% of the states which responded to the current practices survey, approximately 66.7% of them do not require diamond grade sheeting for use in construction zones in their states with cost being the most widely selected reason. Those states that do require diamond grade sheeting for use on drums in their work zones listed safety, improved work zone delineation, and improved work zone visibility as outweighing the cost of the sheeting. Based on the lane placement and speed deviation data, drivers traveling through work zones with diamond grade sheeting position their vehicle further away from the
work zone and abide closer to the posted speed limits when compared to those traveling through work zones with high intensity sheeting on the construction drums.