The contents of this page do not have the force and effect of law and are not meant to bind the public in any way. This page is intended only to provide clarity to the public regarding existing requirements under the law or agency policies. Recipients and subrecipients should refer to FTA’s statutes and regulations for applicable bus testing requirements.

 1.0 Full Testing

Full testing is required for all new bus models. Full testing includes performing, scoring, and reporting data from the complete set of test procedures under the Bus Testing Program, which are:  

• Maintainability
• Reliability
• Safety
• Performance (including Braking Performance)
• Structural Integrity
• Fuel Economy
• Emissions
• Noise

For zero-emission vehicles, the Fuel Economy test measures the vehicle’s energy efficiency and its driving range on a fully-charged energy storage system.  Zero-emission vehicles are not subject to the Emissions test.

2.0 Partial Testing 

The FTA allows variants of bus models that previously completed full testing, and are subsequently produced with major changes, to undergo Partial Testing. When a bus model is eligible for Partial Testing, only those tests in which the data may be expected to be significantly different from the original test data need to be performed. The remaining test data that would not be expected to be significantly different is then obtained from the prior Bus Testing Report on the original bus configuration.

Even if a variant of a previously-tested bus model is eligible for Partial Testing, a manufacturer may choose to submit that new variant for full testing. Opting for full testing offers benefits including avoiding the time required for FTA review of partial testing requirements and making the reporting on that bus model clearer and easier to use. The FTA encourages full testing for variants of older bus models that do not have a Pass/Fail Bus Testing Report.

The essential criteria for determining which test procedures (if any) are required under a Partial Test, is:  

Which test data could reasonably be expected to be significantly different if that test procedure is performed on the revised model?  

A partial list of changes that might result in different data and could require additional testing includes major changes in: 

• Overall vehicle dimensions, weights, or weight distribution
• Primary structural material(s)
• Major load paths
• Number, size, and/or configuration of doors, windows, lifts, ramps, or other structural discontinuities
• Propulsion system
• Number, location, and or powering of axles
• Primary components, especially ones that have not been tested in similar bus models
• Pre-sale modifications by a final-stage manufacturer to a chassis produced by a third party

When an FTA recipient acquires a bus model covered by a Partial Bus Testing Report, the recipient must certify that it possess not only the Partial Testing Report, but also the “baseline” full Bus Testing Report that describes the previously-tested bus model that the new version is based on. In some cases, the recipient may also need to obtain one or more full and/or partial testing report(s) of similar bus(es) that taken together present all the data that would have been included in a full test report of the bus model in question. The reports required in these cases may be specified in an FTA determination provided to the bus manufacturer. Recipients should verify the basis of a manufacturer’s claim that a bus model has satisfied Bus Testing requirements.  

2.1 Determining Partial Testing Eligibility and Requirements

49 CFR § 665.7(b) says, “In dealing with a bus manufacturer or dealer, the recipient [emphasis added] shall be responsible for determining whether a vehicle to be acquired requires full testing or partial testing or has already satisfied the requirements of this part. A bus manufacturer or recipient may request guidance from FTA.”  

If, after reviewing the information on this page and website, you still have questions about Partial Testing requirements for a bus model, you can submit a request for a determination of testing requirements using the FTA Bus Testing Portal.

Sometimes a bus is eligible for Partial Testing but due to the impact of the changes made, FTA would expect different data in most or all of the individual test procedures. In such cases, FTA may determine that Full Testing is required.

If a manufacturer anticipates that Partial (or Full) Testing of the new configuration may be required, they can save time by seeking an authorization to test the bus in the same inquiry, if the required details of the test unit bus can be provided to FTA. See the Determinations and Authorizations page for guidance. 

2.2 Minimizing Overall Testing of Related Bus Models

While specific situations may be different, manufacturers that plan to offer a range of variants of a bus model can sometimes reduce the overall amount of testing required by beginning with full testing of the variant that is:

• Longer/larger
• Heavier
• Has the greatest passenger capacity
• Has more weight on the roof/higher center of gravity
• Is made of stainless steel (rather than mild steel)
• Has a powertrain that provides greater power and/or torque
• Has the greatest fuel tank and/or battery capacity
• Has a greater number of and/or larger body openings (doors, windows, etc.), wheelchair lifts, and/or ramps

These configurations are more likely to represent a “worst-case” configuration. While any change that could result in significantly different data will trigger a requirement for additional testing, FTA generally considers a change that may reasonably be expected to have an adverse effect on the data that would be collected from additional testing to be more significant than a change that might reasonably be expected to result in a favorable effect. For example, moving weight from low in the bus to the roof or vice versa would both affect the stability of the bus (as measured by the Safety test). However, moving the weight higher would adversely affect stability and would likely require repeating the Safety test, while moving the weight lower would favorably affect stability and probably would not require repeating the Safety test.

2.3 Family of Vehicles

The FTA generally permits a manufacturer of a bus body that has been tested on one unmodified third-party chassis to offer the same or closely related body built on another similar unmodified third-party chassis that has been tested at the Bus Testing Center (on one of its own similar buses or on a competitor’s similar bus), without requiring additional testing. This “Family of Vehicles” policy is limited to buses in the 4-year and 5-year service life categories only.

Consistent with FTA’s “worst-case” policy for determining whether additional testing is required, manufacturers should test the longest and heaviest (overall length and wheelbase) version of a bus model in order to minimize requirements for additional testing. 

3.0 Buses not Subject to FTA Bus Testing

Mass-produced vans are thoroughly tested by the manufacturer. Therefore, unmodified mass-produced vans are exempted from FTA Bus Testing, but only in the 4-year, 100,000-mile service life category.  Unmodified mass-produced vans offered in the 5-year, 150,000-mile (or higher) service life category are subject to FTA Bus Testing.

The FTA only requires a Bus Testing Report for buses that are acquired with FTA grant funding.