After numerous shakedown tests, including locating positioning, aiming, adjusting, testing, tuning, and evaluating various proximity warning systems, we concluded that the Doppler radar backup alarms appear to show promise for sensing objects within the blind areas of vehicles. Significant efforts must be made to achieve acceptable performance without false alarms. The Doppler radar discriminating alarm is not a "bolt-on and plug-and-play" unit that is easy to adapt to various situations. During the tests, it was shown that mounting the units to achieve optimum sensing ability without interference and false alarms from other systems was, at the very least, a tedious and time-consuming job. The radio frequency identification (RIFD) tag is currently undergoing antenna design modifications to improve its effective range. This system needs to be designed so that it does not sense more than the desired 40-50 ft (12.2-15.2m) range. The black-and-white closed-circuit television (CCTV) system successfully withstood a year's cycle of loading, hauling, and dumping, as well as the rigors of desert heat and cold. The floor-mounted frame isolated the unit from cab vibrations and offered the driver a single location for visual and verbal communication.
C.M.K. Boldt, NIOSH, Spokane Research Laboratory, 315 E Montgomery Ave, Spokane, WA 99207