(a) The driver of a vehicle, the person in charge of an animal, a pedestrian, and the motorist of a streetcar shall obey the instructions of an official traffic signal applicable to them and placed as provided by law, unless otherwise directed by a police or traffic officer or when it is necessary for the purpose of avoiding a collision or in case of other emergency, subject to the exemptions granted by Section 21055.
(b) (1) A peace officer, as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2 of the Penal Code, shall not stop a pedestrian for a violation of subdivision (a) unless a reasonably careful person would realize there is an immediate danger of a collision with a moving vehicle or other device moving exclusively by human power.
(2) This subdivision does not relieve a pedestrian from the duty of using due care for their safety.
(3) This subdivision does not relieve a driver of a vehicle from the duty of exercising due care for the safety of any pedestrian within the roadway.