The 
coupling alignment 
warning system (CAWS) of the instant invention is designed to provide the driver of a 
towing unit, e.g., a commercial 
truck, with visual and / or audible cues that indicate whether the 
towing unit is aligned relative to a towed unit for proper engagement of the 
coupling components mounted thereon, including a fifth wheel hitch on the 
towing unit and a king pin on the trailer. The CAWS combines a 
laser light source and a series of sensors with a reflective target to provide alignment information to the user. In particular, the 
system combines a low-power 
laser diode mounted on the towing unit with a retro-reflective target that is attached, preferably temporarily, on the towed unit. The target will continuously return positive 
coupling alignment information back to the sensors as long as 
laser light impinges upon the target, i.e., as long as 
target acquisition is maintained. The sensors transmit detection signals to a 
processing unit that includes a 
microprocessor and 
relay. The 
microprocessor is programmed to calculate a threshold level of light that is based on sensed ambient light signals. In operation, the 
microprocessor decodes the detected light and determines whether the detected 
light level reaches the threshold level of light. If so, the CAWS indicates to the user that 
target acquisition has been achieved, and thus, that the towing unit is aligned with the towed unit for positive coupling. The microprocessor also controls the 
relay, thus controlling the delivery of power to the 
laser light source so that the 
system can continually compute an updated threshold level of light based on the ambient light in the surrounding 
operating environment. As a result, the 
system minimizes the chance of triggering on false light signals, notwithstanding varying ambient light conditions. The CAWS is particularly useful in zero or low 
visibility conditions because it can be used in conjunction with mirrors and 
external reference points to provide reliable position information to the user.