Interpretation ID: 7241
Manager, Engineering Services
Blue Bird Body Company
P.O. Box 937
Fort Valley, GA 31030
Dear Mr. Turner:
This responds to your letter asking about Federal Motor Vehicle Safety Standard No. 131, School Bus Pedestrian Safety Devices, with respect to the automatic extension of a stop signal arm. You were especially concerned with the interaction between a provision in Wisconsin's Administrative Code requiring activation of the stop signal arm under specified conditions and the stop signal arm activation requirements set forth in Standard No. 131. I have responded in detail to your questions below.
Before I answer your question about your company's design for complying with both the Wisconsin Code and Standard No. 131, I would like to note that it does not appear that the Wisconsin regulation is inconsistent with Standard No. 131 with respect to the stop signal arm activation requirements. The Wisconsin Administrative Code states that:
"Any bus manufactured after January 1, 1978, shall have the stop signal arm controlled by the service door. The stop signal arm shall not become operational until the service door opens. The stop signal arm shall be installed in such a manner that it cannot be activated unless the alternating red lamps are in operation."
S5.5 of Standard No. 131 states that "The stop signal arm shall be automatically extended in such a manner that it complies with S5.4.1, at a minimum whenever the red signal lamps required by S5.1.4 of Standard No. 108 are activated..." (emphasis added) Both the Wisconsin requirement and the requirement in Standard No. 131 tie the activation of the stop signal arm to the operation of the red signal lamps. In addition, the Wisconsin regulation also ties the activation of the stop signal arm to the opening of the service door. Based on this information, it appears that a manufacturer could comply with both Standard No. 131 and the Wisconsin regulation by designing its school buses so that opening the service door automatically activates both the stop signal arm and the red flashing lamps. If the Wisconsin regulation were interpreted in a way that does not tie the automatic extension of the stop signal arm to opening the service door, then there could be an inconsistency with Standard No. 131.
You asked whether Blue Bird's system for activating the stop signal arm in accordance with Wisconsin's requirement complies with the requirements of Standard No. 131. You explained that, on its school buses sold in Wisconsin, Blue Bird provides a system by which the alternating red flashing lamps are activated by a driver controlled manual switch and the stop signal arm is activated by opening the service door. Under this system, the red flashing lamps are activated before the service door has been opened and before the stop signal arm has been extended. Based on the information provided in your letter, we conclude that Blue Bird's system would not comply with the requirements of Standard No. 131.
Standard No. 131 explicitly requires the stop signal arm to be automatically deployed whenever the red signal lamps required by Standard No. 108 are activated. As explained in the final rule adopting Standard No. 131, "any system of activation is permissible provided the stop signal arm is extended during, at least, the entire time that the red warning lamps are activated." (56 FR 20363, 20368, May 3, 1991). As described in your letter, the system your company has developed for its Wisconsin school buses has the red warning lamps activated by a manual switch and the activation of those lamps does not activate the stop signal arm. Hence, that system does not comply with the explicit requirement of Standard No. 131 that the stop signal arm be automatically extended whenever the red warning lamps are activated.
I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992.
Sincerely,
Paul Jackson Rice Chief Counsel Ref:131 d:6/17/92