Interpretation ID: 7495a
Motor Carrier and Inspection Services
Wisconsin Department of Transportation
4802 Sheboygan Avenue
P.O. Box 7912
Madison, WI 53707-7912
Dear Mr. Walheim:
This responds to your letter seeking a clarification of whether Wisconsin's current requirements for the activation of stop signal arms on school buses would comply with the stop signal arm requirements set forth in Federal Motor Vehicle Safety Standard No. 131, School Bus Pedestrian Safety Devices. Your letter was prompted by my June 17, 1992 interpretation to Blue Bird Body Company. After evaluating the information provided in your letter, together with the information previously supplied by Blue Bird, we have reconsidered our assessment of the Wisconsin requirements. Subject to the qualifications discussed below, it is our reconsidered view that the Wisconsin requirements are not preempted by Standard No. 131 and that Blue Bird can continue to supply buses meeting Wisconsin's specifications, with the addition of the audible warning device described in Blue Bird's letter.
The distinguishing feature of Wisconsin's requirement is that it ties the operation of the stop arm to the opening of the service door, not to the operation of the red flashing lamps. In practice, the lamps on a Wisconsin bus equipped with a four-lamp system would operate like those on a bus equipped with an eight-lamp system, with the red lamps (instead of yellow lamps) flashing while the bus is coming to a stop. Since S5.1.4(b)(ii) of Standard No. 108 requires the yellow lamps on an eight-lamp system to turn off automatically and the red lamps to turn on automatically whenever the entrance door opens, and since the red lamps on the Wisconsin buses would operate whenever the entrance door is open, the Wisconsin buses would conform to the requirements of Standard No. 108. That standard does not prohibit the flashing of red lamps on a four-lamp system while the service door is closed.
For purposes of Standard No. 131, the question is whether there is any circumstance in which the stop arm may be deactivated while the red lamps are flashing. From the standpoint of practicality, we agree with you that the stop arm should not function before the bus has stopped and the driver has opened the service door. We further believe it is consistent with the purpose of the standard for the stop arm to be deactivated on a Wisconsin bus before the bus stops, even though the bus's red lamps may be flashing. To reconcile this view with the language of the standard, however, requires us to address the requirement of the standard that the arm must extend "at a minimum whenever the red signal lamps required by S5.1.4 of Standard No. 108 are activated. . . ."
Standard No. 131 expressly contemplates a situation in which the stop arm would not automatically extend despite the operation of the red lamps. The final clause of S5.5 provides that "a device may be installed that prevents the automatic extension of a stop signal arm." The question in Wisconsin's situation is whether the manual switch that activates the red signal lamps but not the stop arm would qualify as such a device. In our view, it does. Since the only time the red lamps are required by Standard No. 108 to operate is when the entrance door is open, and since the Wisconsin system would automatically extend the stop arm when the entrance door opens, we believe that the manual switch in the Wisconsin system can be fairly characterized as an override device that prevents the automatic extension of the stop signal arm until the red lamps are required to operate. For an override to be permitted, the device must comply with the other provisions set forth in S5.5, including the presence of a continuous or intermittent signal.
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:9/14/92