SAFETY STUDY
Adopted: November 30, 1988
BRAKING DEFICIENCIES ON
HEAVY TRUCKS IN 32 SELECTED ACCIDENTS 

NTSB NUMBER: SS-88/06 
NTIS NUMBER: PB88-917008


SYNOPSIS
Heavy truck braking performance is affected by the maintenance of the braking system. If parts of the system are inoperative or not functioning properly, system performance deteriorates. Of the 189 cases investigated by the Safety Board, this safety study focuses on 32 cases that involved heavy trucks with brake problems. Of these 32 accidents, one of the most prevalent vehicle-related safety issues that surfaced was out-of-adjustment brakes. The report concludes with recommendations to the National Highway Traffic Safety Administration, the American Trucking Associations, and the National Private Truck Council.

RECOMMENDATI0NS

As a result of this study, the National Transportation Safety Board recommends:

to the National Highway Traffic Safety Administration:

Publish a final rule by June 1990 that will require automatic stack adjusters on all new trucks equipped with air/mechanical brake systems. (Class II, Priority Action)(H-88-30)

to the American Trucking Associations and the National Private Truck Council:

Recommend that your member carriers adopt written policies regarding on-the-road brake adjustment; if the drivers are responsible for performing such adjustments, provide them with the necessary training. (Class II, Priority Action)(H-88-31)

Recommend that your member carriers, as they replace worn brake chambers, install airbrake actuation devices that incorporate indicators to warn users when brakes must be adjusted. (Class II, Priority Action) (H-88-32)