Abstract: A work brake system applies a reduced air pressure service brake application as a work brake to hold a heavy duty vehicle in place without actuation of conventional spring brakes during frequent start-and-stop operations of the vehicle, such as in refuse collection. The work brake system includes fail safe features to prevent vehicle roll in the event of loss of air pressure, by providing separate primary and secondary sources of pressurized air, and by automatically diverting to application of spring brakes in the event of primary pressure or signal loss.