Section 25273 Of Article 7. Flashing And Colored Lights From California Vehicle Code >> Division 12. >> Chapter 2. >> Article 7.

. Any motor vehicle owned and operated by a school district with an average daily attendance in excess of 400,000 while being used to measure the distance from school to a school pupil's residence may display a flashing amber warning light to the rear of the vehicle when moving at a speed substantially slower than the normal flow of traffic.