Current innovations in Doppler radar technology have led to suggestions by several institutions and manufacturers that new backup alarm systems are available that can replace or augment warning systems for backing operations on large haulage vehicles. In 1995, Spokane Research Laboratory engineers contacted research institution, equipment manufacturers, and vendors to determine the availability of such systems. Only tow manufacturer-vendors of the radar backup alarms were found. In both cases, the units had not been tested on large, off-road mine haulage trucks. A series of laboratory tests, controlled simulated tests on small vehicles, and full-scale field tests on 240-ton class, end-dump haulage trucks were conducted to evaluate the existing devices.