21 . A steady yellow traffic signal light is a warning that the light is about to change to red. If you are already within the intersection when a green light changes to yellow, you should:
Stop.
Continue moving and clear the intersection safely.
Increase your speed so as not to cause an accident.
35 . You are approaching a railroad crossing with no warning devices and are unable to see 400 feet down the tracks in one direction. The speed limit is: