A tow aid system used while operating a wrecker adapted to tow a vehicle, the wrecker comprising an underlift arm extending rearward from the wrecker, wherein the underlift arm is adapted to lift at least a part of the vehicle for towing. The tow aid system comprises: axle load sensors mounted along different longitudinal positions on the wrecker, the axle load sensors generating signals indicative of loads along the different longitudinal positions; an underlift arm load sensor mounted about the underlift arm, the underlift arm load sensor generating signals indicative of a load applied on the underlift arm while holding the vehicle in a towing position; and a controller processing the signals from the axle load sensors and the underlift arm load sensor to calculate operating limits of the wrecker.