It is more like car length than seconds when following another car. You should be at least 2 car lengths from the other car.
Not sure if you are talking about a vehicle for a disabled person or a vehicle that is disabled on the side of the road. If its the former then there are no special lights. If its the latter then the hazard lights on the vehicle will either be amber in the front and rear or amber in the front and red in the rear. Most vehicles the hazards are amber in the front and rear though
1) within 10 ft. of the front or rear of vehicle 2) 100 Ft. at the rear of the vehicle 3) 100 Ft. at the front of the vehicle
In clear weather conditions, 2 seconds.
A driver should stay at least two seconds behind any vehicle that is directly in front of the driver's vehicle.