Barricade warning lights have been used for many years at construction sites to indicate to drivers that caution is needed. A benefit of these warning lights is that they are widely recognized and understood, but a downside is that "caution" is the only message that they are able to communicate. Drivers may not know what action should be taken until additional information is available, or it is too late.
Through the Region II University Transportation Research Center’s (UTRC’s) Research Initiative, the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute proposes to develop a new barricade lighting system that will go beyond "caution" to provide important information about the construction site by utilizing a number of unique features available through LED lighting technologies. Different colors, spatial arrays, and temporal profiles can be used in conjunction with wireless controls and radar speed measurements to communicate important information visually about the construction site.
The four signals used in the barricade lighting system, their anticipated effect on driver behavior in comparison with standard Type B amber barricade warning lights, the construction zone situation in which they???d be used, and the performance measurement are:
- Signal: flashing green light. Anticipated driver behavior: proceed through at higher speed. Used when: work zone is unoccupied and drivers can proceed through at the normal speed limit. Performance measurement: speed and deceleration.
- Signal: flashing red light. Anticipated driver behavior: reduce speed more sharply. Used when: there is stopped or extremely slow traffic immediately ahead, as indicated by radar. Performance measurement: deceleration, distance from obstacle at which car comes to a stop.
- Signal: "shifting" yellow light (a circular light that fills from left to right or from right to left indicating direction of needed lane shift). Anticipated driver behavior: change lanes sooner. Used when: there is a lane closure. Performance measurement: distance ahead of lane closure that drivers shift lanes.
- Signal: "looming" yellow light (a circular light filling outwardly from the center). Anticipated driver behavior: drive slower. Used when: work zone is staffed and great caution is needed. Performance measurement: speed and deceleration.
To determine the effectiveness of this barricade light system, the flash patterns described above will be tested on a closed track. Test subjects will drive a car- instrumented to measure throttle variation, braking, speed, and position- through the track set up with barricades and other indicators to simulate the four situations described above. Measured performance will be compared between runs with the barricade lighting system and runs with standard barricade warning lights to determine if the barricade lighting system has the anticipated effect on driver behavior.
The project team will include LRC researchers from the transportation and the solid-state lighting programs. A work product for the evaluation will include a technical report summarizing the assessment and providing guidelines on how this signaling system might be used.
Video of the experimental sessions for the barricade lighting system evaluation conducted on November 2010.