摘要: |
This research focuses on the development and evaluation of a truck monitoring and warning (TM&W) system for detecting high, long, fast, trucks at freeway-to-freeway connections and activating displays to warn the truck drivers of potential hazards as their vehicles approach the curved section of an interchange ramp. The basic study was conducted on the elevated left-turn ramp for traffic southbound on I-610 loop freeway to eastbound on SH 225 (LaPorte Freeway) in Houston, Texas. The TM&W system used three infrared light-beam sensors with a special microcontroller-based signal processor, named TDA3 (Traffic Data Acquisition), to determine the speed, length at 7 ft (2.1 m) above the road surface, and arrival time for every vehicle that blocked the light beams. When selected criteria were met, the TDA system sent a warning message to the driver. Software for data collection and processing was developed, and before-and-after speed-change studies were conducted to determine the effect of applying the truck monitoring and warning system at the curved, elevated interchange ramp. The results of this research indicate that activating flashing-yellow-light warning displays for only the trucks exceeding the preset criteria caused an average additional 2 mi/h (3.2 km/h) speed reduction, beyond normal, before the trucks entered the curved portion of the ramp. Recommendations are made for potentially improving the impact of the warning message on drivers. |