Crash Conferences for Accident Reconstruction

2009 ARC-CSI Crash Conference Presentation

Commercial Vehicle Air Brake Performance
Presented By: Phil Smith & Timothy J. Reust
Time: 2 Hours

Air brakes on commercial vehicles are very different to the brakes found on passenger type vehicles. When reconstructing an event involving a commercial vehicle, knowledge of air brake performance is beneficial.

The details of instrumented tests will be presented to cover deceleration rates and lag times. The lag times will include brake pedal initiation to when the air pressure first begins to increase in the brake chamber, when the pushrod first begins to move and when skidding first begins. A look at the steer axle brakes, drive axle brakes and trailer brakes will contrast the difference of what takes place at each axle during the braking process and show how the ABS system is functions.

Different conditions will be covered to include dry road, wet road, empty and loaded trailer and bobtail.

Phil Smith

Timothy Reust

About Phil Smith

Philip J Smith (Phil) is a certified ASE Master Medium/Heavy Truck Technician and ASE Master Automobile Technician. He lives in Grand Junction Colorado. He has had his own consultant company since 2000. He is a licensed private investigator. He is a co-owner in a company that encompasses the manufacturing of an applied patented electronic data acquisition device for the testing of tractor-trailer air brakes.

Phil grew up in a family with a truck business. He started relining brake shoes at 12 years old. And has been working with brake systems ever since.

He consultant on driver’s actions, responsibilities, qualifications, training, compliance and safety.

He is certified in Wabco, Midland-Grau and Bendix ABS Systems.

About Timothy J. Reust

Mr. Reust is based in the Los Angeles area and is an engineer with more than 20 years of experience in the field of accident reconstruction; in addition to reconstruction he has specialties in instrumented vehicle testing and event data recorder downloading and evaluation for both passenger vehicles and commercial vehicles. He consults and lectures throughout the United States and Canada on issues related to event data recorders.

Mr. Reust has conducted many instrumented tests to measure the acceleration and braking performance of a wide variety of vehicle types including commercial vehicles, passenger vehicles, emergency vehicles, bicycles and scooters.

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