Interpretation ID: aiam0120
Executive Vice President
Truck Body and Equipment Association
Inc.
1012 Fourteenth Street
N.W.
Washington
DC 20005;
Dear Mr. Sweet: Thank you for your letter of September 12, 1968, to Mr. J. E. Leysat of this Bureau, requesting a clarification of the aiming requirements for school bus signal lamps as specified in Federal Motor Vehicle Safety Standard No. 108.; Paragraph S3.1.3.1 of Standard No. 108 specifies that red school bu signal lamps shall conform to SAE Standard J887, 'School Bus Red Signal Lamps,' July 1964, and that amber signal lamps shall conform to the same SAE Standard except for color and candlepower requirements. In the last paragraph of SAE Standard J887, aiming requirements are specified as follows: 'Lamps should be mounted on the school bus with their aiming plane vertical and normal to the vehicle axis. A suggested tolerance for this aim is 5 inches at 25 feet in vertical aim and 10 inches at 25 feet in horizontal aim. If lamps are aimed or inspected with a mechanical headlamp aimer (see SAE J602) the graduation settings for aim should be 2 down and 0 sideways. The limits for inspection should be from 3 up to 7 down and from 10 right to 10 left.'; In accordance with the above quoted paragraph, either visual o mechanical aiming of the signal lamps is permitted. Therefore, the graduation settings and inspection limits, as specified in the last two sentences of the paragraph, are applicable only when a mechanical headlamp aimer is used to aim the signal lamps.; Thank you for writing. Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service;