In 2003 and again in 2004, the Commercial Vehicle Safety Alliance conducted continent-wide surveys of drivers' brake system knowledge. The results were shocking.

As part of Operation Air Brake 2003, CVSA polled 4,055 commercial drivers across 60 jurisdictions. Of those drivers, only 15 (0.0037%) provided the correct response to all questions involving knowledge of brake deficiencies and adjustment.

In 2004, CVSA tried again. Using a true and false format, the questionnaire, among other things, asked drivers to identify all four of the conditions required to properly inspect brake adjustment. Only 192 of more than 4,000 drivers surveyed correctly identified all four.

For example, almost three-quarters of the respondents indicated that the service brakes needed to be released or only partially applied when checking brake stroke. In fact, 62% of drivers indicated they used incorrect and unreliable methods of determining brake adjustment, including the "feel" of the brakes and the pressure drop during an application.

Drivers didn't do any better in their knowledge of compliance issues or their understanding of automatic brake adjusters.

"The results of surveys continue to indicate that drivers are not as familiar with their brake systems as we would have expected," says CVSA'sWilliam Schaefer, director of vehicle programs. "I don't think there has been a significant improvement in those statistics since 2003 and 2004."

He says that while drivers are not mechanics or brake technicians, they should be able detect some basic brake system deficiencies.

"For the purposes of a pre-trip inspection and in the handling of the vehicle, they should be able to notice loose components, poor adjustment, greased linings, etc.," he says.

"While I think their understanding of the basic brake system is inadequate, I also think we - enforcement, industry, advocacy groups, etc. - need to give them better tools to help them determine when their brake systems are deficient and when the vehicle should not be driven."

Do you rely on driver reports concerning brake system function and compliance? If so, you might want to ask how much your drivers really know about their brake systems, and how thorough a job they do in inspecting those systems.

From the September 2012 issue of HDT