在加州用行车记录仪录30 秒的问题 ?

在加州的那位用行车记录仪， 加州的法律规定可以用行车记录仪，但是只能录发生事情的前后30秒。我一直没弄明白这个，有那位懂能给讲讲吗？ 看看C 这条的规定。现在的行车记录仪都是循环一直在录的。

(13) (A) A video event recorder with the capability of monitoring driver performance to improve driver safety, which may be mounted in a seven-inch square in the lower corner of the windshield farthest removed from the driver, in a five-inch square in the lower corner of the windshield nearest to the driver and outside of an airbag deployment zone, or in a five-inch square mounted to the center uppermost portion of the interior of the windshield. As used in this section, “video event recorder” means a video recorder that continuously records in a digital loop, recording audio, video, and G-force levels, but saves video only when triggered by an unusual motion or crash or when operated by the driver to monitor driver performance. 
(B) A vehicle equipped with a video event recorder shall have a notice posted in a visible location which states that a passenger’s conversation may be recorded. 
(C) Video event recorders shall store no more than 30 seconds before and after a triggering event. 
(D) The registered owner or lessee of the vehicle may disable the device. 
(E) The data recorded to the device is the property of the registered owner or lessee of the vehicle. 
(F) When a person is driving for hire as an employee in a vehicle with a video event recorder, the person’s employer shall provide unedited copies of the recordings upon the request of the employee or the employee’s representative. These copies shall be provided free of charge to the employee and within five days of the request.