The requirement to have a CDL in order to drive a CMV (Commercial Motor Vehicle) has been mandatory since 1992, however a CDL by itself is not enough. Depending on the type of vehicle a driver operates, he or she may still be required to undergo testing for one or more CDL endorsements. Normally, the most common type of endorsement required is the one for air brakes. Air brakes are the most efficient and effective type of braking system for large, heavy vehicles but their use and maintenance requires special knowledge on the part of the commercial driver.

Air brakes normally consist of three different braking systems: the service brake, parking brake, and emergency brake. The service brake system operates when the brake pedal is used during normal driving. The parking brake system operates when the driver uses the parking brake control. The emergency brake system kicks in to stop a vehicle during brake system failure, and utilizes parts from both the service brake and the parking brake.

Knowing first what kind of air brake system a driver will operate should be top priority. If a driver is going to pursue an air brake endorsement, these are the things he/she should know first:

• Air Brake System Parts
• Dual Air Brake Systems
• Inspecting Air Brakes
• Using Air Brakes

Air Brake System Parts

Air brake systems are not standard on all vehicles; there are different types of systems depending on the make of the vehicle, and the date it was manufactured. There are many parts to an air brake system, and having an intimate knowledge of what each part does will make it easier for a driver to diagnose a potential problem. There are parts that are specifically designed to alert the driver if there's anything wrong, and knowing these parts is the key to maintaining proper air brake functionality in a vehicle.

Dual Air Brake Systems

Most of the bigger vehicles utilize a dual air brake system connected to one set of brake controls. These systems, designed for safety, control two separate sets of brakes for the front and rear axles. Maintaining proper air pressure in both the primary and secondary system is key to maintaining harmony in the dual system. Should the pressure in either system drop to 60 psi or lower, it will turn off that brake system and it will take longer for the vehicle to come to a complete stop. Should this happen, the safest option is parking the vehicle in the nearest available stop and getting the brake systems fixed.

Inspecting Air Brakes

There are more parts to inspect in a vehicle with air brakes than one without, and knowing how to properly inspect the parts for any possible trouble is key to maintaining safe vehicle operation. Since air brakes operate on compressed air, there will be several gauges and warning lights in the vehicle that would tell if air pressure is at optimum working efficiency. If there is any suspicion that the system is not working properly, the driver needs to take immediate action to prevent longer braking or the need to rely on the emergency brake due to failure of the system.

Using Air Brakes


Knowing how to use the braking systems properly is the first step in making sure that the air brake system(s) will last for a long time. Knowing how to perform emergency stops while the ABS (Antilock Braking System) is on, remembering to use the parking brake system, and knowing the proper stopping distance for the vehicle a driver would be operating are what makes for safe operation of vehicles with air brake systems.

In order to get proper training for air brake endorsement, a driver must pass a written exam, and perform specific maneuvers on the vehicle they plan to operate, in order to gauge their knowledge about air brake systems.

Learn more about how to get you CDL or take a FREE Air Brakes test at TestQuestionsAndAnswers.com.

Labels: air brakes, cdl, CDL endorsements, CDL practice test, commercial drivers license, commercial truck drivers, commercial vehicles

A new rule was adopted in April by the Federal Motor Carrier Safety Administration (FMCSA) that will require installation of Electronic Onboard Recorders (EOBRs) most interstate commercial vehicles by June of 2015. EOBRs are designed to electronically monitor compliance with Hours of Service (HOS) rules by commercial drivers.

The new rule, which was endorsed by major trucking associations, including the American Trucking Association, the National Private Truck Council, and the Truckload Carriers Association, hasn't been welcomed by all. Many independent truckers look on the rule as an unnecessary regulatory intrusion and an economic burden. Safety advocates however, view the rule as long overdue.

Onboard electronic monitoring of a trucker's speed, and time spent in motion have been around for quite some time and many trucking companies have embraced the technology. Trucking company who use the technology can better determine exactly how long a particular delivery takes and adjust their pricing and contractual delivery time more accurately. Another benefit is safety related. Through the use of GPS and engine monitoring systems, trucking companies can monitor whether or not their drivers are obeying speed limits and complying with HOS rules. The safety benefit has shown to be a great benefit to trucking companies in reduced liability for collisions due to speeding or sleep deprived drivers.

The FMCSA, which regulates interstate commercial vehicles, has been slow to adapt to the new technology, relying instead on hand written log books kept by the drivers to show they are in compliance with the mandatory HOS rules. The problem with that is that hand written logs are notoriously easy to fake and it is difficult to tell whether or not a driver has been on the road too long and is possibly sleep deprived.

A year after the federal HOS rules last changed in 2004, the Insurance Institute for Highway Safety (IIHS) conducted a study to see if drivers were complying with the rules that limited their time on the road and required specified rest periods. The study found that 25% of the drivers admitted to driving more hours and the number of drivers who reported driving drowsy or falling asleep at the wheel within the previous month rose from 13% to 15%.

Drivers feel great pressure to meet delivery deadlines, especially when the cargo is perishable or otherwise time sensitive. Many drivers feel compelled to speed or to push on, even when they are drowsy, to meet the contracted delivery schedules. The ability to easily falsify log books, for the most part, eliminated the consequences of non-compliance, unless the speeding or drowsy driving led to a crash.

Driving drowsy is a significant danger for commercial drivers. Since most instances of a collision caused by sleep deprivation require self admission by the driver, it is difficult to come up with accurate figures on the true number of crashes caused by drowsy commercial drivers however, based on surveys and the types of crashes (swerving into adjoining lanes etc.), the IIHS determined that at least 13% (18,000) of crashes involving commercial truckers were due to driver fatigue.

The latest figures from 2009 show that there were 3,163 fatalities in crashes involving large trucks. Truck occupants made up only 14% of the fatalities. Drivers of cars and other passenger vehicles made up 70% of the fatalities with the rest made up of pedestrians, bicyclists and motorcyclists. Of those involved in two-vehicle crashes between large trucks and passenger vehicles, 98% of the deaths were the occupants of passenger vehicles.

The new rules requiring electronic monitoring will go into effect in June of 2012 with full compliance required within three years of that date. Both the federal government and trucking associations, say that the EOBR's will make operations smoother and less expensive by eliminating the inefficient paper trail and allowing an automatic download of driver records at state inspection stations. Safety advocates laud the new regulations in the hope that they will help to end instances of fatigued drivers pushing on long after federal regulations say they should have pulled off the road to rest.

Labels: commercial truck drivers, commercial vehicles, gps devices, Onboard electronic monitoring, truck safety