Commercial Vehicle Air Disc Brake Operation and Adjustment
Government inspection data (gathered from random road-side inspections), has repeatedly highlighted the need for better maintenance and monitoring of brake operation and adjustment on commercial air disc brake equipped vehicles. A recent CVSA road check program was conducted in June 2013, and the inspection and out-of-service (OOS) data is quite revealing.
73,023 truck and bus inspections were conducted (including 1,471 motor coaches)
47,771 Level 1 inspections (which includes brakes) were conducted
24.1% of the vehicles (of the 47,771 inspected) were found with OOS violations
Brakes routinely stood out in the mix of OOS violations issued
49.6% of vehicle OOS violations were related to brake adjustment
287 inspections were conducted with Performance Based Brake Testers (PBBT) Vehicle Deceleration
12.5% vehicles were found (of the 287 inspected) with overall brake efficiency below theminimum required by US regulation and the North American Standard OOS criteria. As foundper PBBT testing of each vehicle.
Scientific study, as well as forensic accident investigations by NTSB (National Transportation Safety Board), has well documented the link between vehicle brake defects and accident causation and severity. A recent study by the University of Michigan Transportation Research Institute (UMTRI), scientifically analyzed data from of The Large Truck Crash Causation Study (LTCCS) conducted by FMCSA and NHTSA during 2001 to 2003. This data set is the largest and most well-known study conducted involving commercial vehicle accidents and their causation. By carefully analyzing the data from this study, UMTRI proved that the only vehicle mechanical defect that can be directly linked to accident causation is brake defects. Highlights from this UMTRI study revealed:
The sample size was 963 crashes involving heavy trucks
Actual physical inspections were performed on 1001 trucks in this study
Brake adjustment data was available on 826 trucks
33% of the trucks involved had at least one brake CVSA OOS condition
20% of the trucks involved would have been put out of service due to 20% or more of the
vehicles brakes being defective
Brake violations were the highest among all mechanical systems inspected
Of all mechanical defects, only brake adjustment was found to have a statistically
significant relationship to accident causation
No other mechanical defect was found to be statistically significant
A vehicle is 1.8X more likely to be the striking vehicle in a brake related collision if its brakes are out of adjustment. This likelihood increases to 3.5X more likely if the vehicle is loaded. In addition, the NTSB has recently conducted two accident investigations where there was loss of life, and found in both cases that defective brakes were a causal factor in the likelihood and severity of the accidents. The first case involved a collision between a Tractor-Trailer and an Amtrak passenger train in Miriam, Nevada in 2011 and the second case involved a collision between a Truck and School Bus in Chesterfield, NJ in 2012. As a result of these two accident investigations, NTSB has issued two recommendations to National Highway Transportation Safety Administration (NHTSA) concerning vehicle braking safety technology.
H-12-58: Develop minimum performance standards for onboard brake stroke monitoring systems for all commercial vehicles
H-12-59: Once the performance standards in Safety Recommendation H-12-58 have been developed; require that all newly manufactured air-brake commercial vehicles be equipped with onboard brake stroke monitoring systems.
Leave words, your message replied in 24hours.
Toget Brake
Brand Vision:"to become the China leading supplier of active vehicle safety systems within the commercial vehicle industry."
At Toget, focus on air disc brake calipers technics, exceeding industry standards is a strict requirement.
Brand names, original numbers, vehicle mark and models are only for reference purposes.
