An intermodal chassis for highway transportation of shipping containers, the chassis having a forward axle and a rear axle, and incorporating an air bag suspension that automatically deflate the air bags when the brakes are locked, preventing damage when loading a container onto the chassis. Large 53 foot long box/high cube type shipping containers may be loaded along their entire length with the chassis having a rear axle positioned under the chassis frame so that the kingpin-to-rear-axle length is no more than 40 feet, and a forward axle positioned under the frame between the gooseneck and the rear axle so that a forward-to-rear-axle length is at least 12 feet. Other features include self-scaling and load-leveling, and other weight savings include use of smaller sized aluminum wheels.