Many trucks had "wet pavement" switches that completely shut off the air supply to the brakes on the steering axle. Many carriers even went so far as to remove steering axle brakes completely. However, these devices became illegal in 1975 The idea was that if the steering axle tires locked up the vehicle be out of control. In 1997 ABS became mandatory. The Texas DPS puts any commercial vehicle with steering axle brakes disabled out of service.
