§571.125. Standard No. 125; Warning devices. — Inbound Citations

(1) Three bidirectional emergency reflective triangles that conform to the requirements of Federal Motor Vehicle Safety Standard No. 125, § 571.125 of this title; or

(c) The vertical centerline of the stop signal arm is not less than 9 inches away from the side of the school bus.

S5.4.2 A second stop signal arm may be installed on a school bus. That stop signal arm shall comply with S5.4 and S5.4.1.

S5.5 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; except that a device may be installed that prevents the automatic extension of a stop signal arm. The mechanism for activating the device shall be within the reach of the driver. While the device is activated, a continuous or intermittent signal audible to the driver shall sound. The audible signal may be equipped with a timing device requiring the signal to sound for at least 60 seconds. If a timing device is used, it shall automatically recycle every time the service entry door is opened while the engine is running and the manual override is engaged.

S6 Test Procedures.

S6.1 Reflectivity Test. When tested under the conditions specified in S6.2 (b), (c), and (d) of Federal motor vehicle safety standard 125, Warning Devices, (49 CFR 571.125), the retroreflective materials shall meet the criteria specified in table 1.

S6.2 Lighting Tests.

S6.2.1 Color. The procedure shall be done in accordance with SAE Recommended Practice J578-1988 (incorporated by reference, see § 571.5). When visually compared to the light emitted from a filter/source with a combination of chromaticity coordinates as explained in SAE Recommended Practice J578-1988 within specific boundaries [y = 0.33 (yellow boundary) and y = 0.98— × (purple boundary)] the color of light emitted from the test object shall not be less saturated (paler), yellower, or purpler. The test object shall be placed perpendicular to the light source to simulate lamps on stop signal arms. In making visual comparisons, the light from the test object shall light one portion of a comparison field and the light from the filter/source standard shall light an adjacent area. To make a valid visual comparison, the two fields to be viewed shall be of near equal luminance.

S6.2.2. Flash rate. The lamps on each side of the stop signal arm, when operated at the manufacturer's design load, shall flash alternately at a rate of 60 to 120 flashes per minute.

S6.2.2.1 Lamps, except those subject to S6.2.2.2, shall have a current “on” time of 30 to 75 percent of the total flash cycle. The total current “on” time for the two terminals shall be between 90 and 110 percent of the total flash cycle.

S6.2.2.2 Xenon short-arc gaseous discharge lamps shall have an “off” time before each flash of at least 50 percent of the total flash cycle.

S6.2.3 Vibration, Moisture, Dust, Corrosion, Photometry, and Warpage Tests. The procedure shall be done in accordance with SAE Recommended Practice J575-1983 (incorporated by reference, see § 571.5) and SAE Recommended Practice J1133 (1984) (incorporated by reference, see § 571.5). Lamps and lighting components shall meet the criteria for vibration, moisture, dust, corrosion, photometry, and warpage in SAE Recommended Practice J575-1983 and SAE Recommended Practice J1133 (1984) under the test conditions specified herein.

(2) ASTM B117-64, “Standard Method of Salt Spray (Fog) Testing,” revised 1964, into § 571.125.