All vehicles using the public highway must adhere to the provisions of the Road Vehicles Lighting Regulations 1989, as amended. Amendments were made in 2005 which allowed cycles to exhibit flashing lights (4 candelas; flash rate 1-4 times per second) front, rear and side (e.g. set in the wheels) whereby red is reserved for rear only, front may exhibit a range of colours (e.g. white, yellow, green amongst others) and amber tends to signify side placement. However blue lights are exclusively reserved for emergency vehicles.