Portable, Non-Intrusive Advance Warning Devices for Work Zones With or Without Flag Operators

The main objective of this study was to develop a work zone alert system informing speeding drivers of the upcoming work zone and raising their attention level before they reach the taper line and/or the work zone flag operator. The resulting system, termed Intelligent Drum Line (IDL), is capable of delivering visual and auditory warnings, targeting vehicles that are exceeding the posted or temporary speed limit upstream of the work zone. The IDL system, in its final incarnation, is the best compromise that can be reached between developing a low-cost system that is rugged enough to be deployed on the shoulder of high-speed roadways and comprised of as few individual parts as possible so a single work zone worker can deploy and move the system as the work zone operations are progressing and delivery of a warning targeted only at vehicles that are going faster than the desired speed set by the work zone crew. The IDL system has been tested in the MnROAD facility, targeting vehicles ranging from regular passenger vehicles to a 3-ton snowplow truck. The auditory warning has been successful in penetrating the vehicle cab and loud enough to attract the attention of the driver. Although, still in a prototype stage, the IDL system has received high marks from MnDOT engineers and work zone workers. Further development is needed to ensure that the final product is crash proof and that it can be produced efficiently.