bus tests

Safety   |   Structural Integrity & Durability  |   Reliability   |   Performance   |   Maintainability   |   Noise

Fuel Economy   |   Emissions

Introduction
Upon arrival at the Altoona Bus Research and Testing Center, each bus undergoes a detailed check-in procedure. The objective of the check-in procedure is to document the "as arrived" condition and configuration of the new model bus. Nine tests are then performed on the buses: safety, structural integrity and durability, reliability, performance, maintainability, noise, fuel economy, brake, and emissions. These are not pass-or-fail tests; the data from all the tests are compiled into a test report that is made available to the manufacturer to provide information during the procurement process.



Safety
The objective of this test is to determine handling and stability characteristics of the bus by measuring the forward speed through a double lane change, obstacle avoidance course [read full test procedure].





Structural Integrity & Durability
There are seven procedures that comprise this testing sequence.

Shakedown: The objective of this test is to determine certain structural characteristics (e.g., bus frame deflection, permanent structural deformation, etc.) under static loading conditions [read full test procedure].

Distortion: The objective of this test is to observe the operation of various subsystems when the bus is placed in a longitudinal twist (simulating operation over a 6-inch curb or through a 6-in pothole) and subjected to a water spray mechanism simulating rain and traffic spray [read full test procedure].

Static Tow: The objective of this test is to determine the strength characteristics of the bus towing fixtures during static loading conditions [read full test procedure].

Dynamic Tow: The objective of this test is to verify the integrity of the towing fixtures and determine the feasibility of towing the bus using a heavy-duty wrecker and specified procedures [read full test procedure].

Jacking: The objective of this test is to determine the damage caused by a deflated tire and to determine the feasibility of jacking the bus with a portable hydraulic jack to a height sufficient to replace a deflated tire [read full test procedure].

Hoisting: The objective of this test is to determine possible damage or deformation caused by the jack stands on the jacking pads [read full test procedure].

Durability: The objective of this test is to perform an accelerated durability test that approximates up to 25 percent of the service life of the vehicle [read full test procedure].







Reliability
The objective of this test is to evaluate the reliability of the bus by documenting unscheduled breakdowns, repairs, down time, and repair time that occur during testing [read full test procedure].







Performance
There are two tests that comprise the performance test sequence.

Gradeability: The objective of this test is to determine the acceleration, gradeability, and top speed capabilities of the bus. The time-to-speed for sequential speed increments at full throttle is measured using a stopwatch with a lap timer and later used to generate a speed versus time plot and gradeability calculations [read full test procedure].

Brake Performance: The objective of this test is to demonstrate the ability of the parking brake to hold the bus on a 20 percent grade and to measure the stopping distance required when the service brakes are activated at various speeds [read full test procedure].







Maintainability
There are three procedures that comprise this test sequence.

Accessibility of Components and Subsystems: The objective of this test is to check the general accessibility of components and subsystems. Items that are checked are ones that would typically require maintenance or repair during transit service [read full test procedure].

Servicing, Preventive Maintenance, and Repair Maintenance: The objective of this test is to collect data about the servicing, preventive maintenance, and repair of the vehicle [read full test procedure].

Replacement and/or Repair of Selected Subsystems: The objective of this test is to identify the time required to replace and/or repair selected parts or subsystems [read full test procedure].







Noise
There are two procedures that comprise this test sequence.

Interior Noise: The objective of these tests is to measure and record interior noise levels and check for audible vibration under various operating conditions [read full test procedure].

Exterior Noise: The objective of this test is to record exterior noise levels when a bus is operated under various conditions [read full test procedure].







Fuel Economy
The objective of this test is to provide accurate comparable fuel consumption data on transit buses produced by different manufacturers. This test bears no relation to the calculations done by the Environmental Protection Agency. The results of this test will not represent actual "in service" fuel economy but will provide comparative data [read full test procedure].







Emissions
The objective of this test is to provide accurate, comparable gas and particulate emissions data for transit buses produced by different manufacturers while operating the vehicle over a simulated transit duty cycle on a dynamometer [full test procedure available soon]. The test will be performed on a engine after the bus has accumulated several thousand miles of operation, thus providing a more realistic indication of the level of emissions that can be expected in actual transit service. The results of this test may be used by transit operators for making relative comparisons between buses.

This is not the same procedure that is used to meet the Environment Protection Agency (EPA) compliance testing.