Evaluating pre-impact acceleration and braking is an important aspect of reconstructing collisions. These performance characteristics are well documented for many vehicle classes, but are limited when discussing modern fire apparatus designs. These vehicles are engineered to be well-balanced, but are typically heavy due to the amount of equipment and fluids onboard. Manufacturers have basic production designs that serve as the platform for custom specification orders from the end-user.
The emergency driving conditions in which they operate constantly challenge the vehicle components, including the brake systems. Because of the heavy weights and operating conditions, auxiliary brake systems are often installed to provide additional braking capabilities as well as prolong the life of the service brakes.
A series of acceleration and braking tests were conducted using heavy fire apparatus of several classifications. Braking tests were conducted using the service brakes, both with and without the available installed auxiliary braking devices. Data was collected using accelerometers, video, and ground measurements. The target speed for these tests was 64 kph (40 mph).
This paper addresses the results of these tests and previously completed similar performance tests of modern fire apparatus designs.