Interpretation ID: aiam1660
Product Engineer-Advanced Design
The Flxible Company
Loudonville
OH 44842;
Dear Mr. Frye: This responds to Flxible's October 11, 1974, petition to exempt th 'trackless trolley coach' category of bus from the requirements of Standard No. 121, *Air brake systems*. You describe the vehicle as similar to your diesel bus but without the weight of the diesel engine, and with electrodynamic braking provided by the traction motor to a maximum of 2.0 mph per second in conjunction with brake operation.; I have enclosed a copy of our letter to Flyer Industries Limited on th same subject. The letter describes our position with regard to status of the trackless trolley as a motor vehicle, and also how it must be tested under Standard No. 121.; You have noted several difficulties in testing a vehicle which use overhead electric lines as a source of power. I would like to point out that, as we interpret the National Traffic and Motor Vehicle Safety Act of 1966, we have established the policy that a manufacturer may conduct certification testing in any manner it chooses, as long as it is calculated, in the exercise of due care, to demonstrate that the vehicle would pass if tested as specified in the standard. Thus, you would be free to certify the vehicle based on tests without use of overhead lines and the benefit of electrodynamic braking. We understand from your letter that without the weight of the diesel engine the trackless trolley has better braking performance than the equivalent diesel engine.; At this time we have issued a proposal that would establish specia test conditions for certain vehicles and limited exemptions for other vehicles, based on their configuration. We will consider your letter as a petition under this rulemaking action, and we invite you to make further comments to Docket 74-10, Notice 7, within the next 30 days.; We will advise you of our determination by letter or by notice in th *Federal Register*.; Yours truly, Richard B. Dyson, Acting Chief Counsel