Each site of enforcement will have signage that applies specifically to that route and what the restrictions are. As part of obtaining a driving licence there is an expectation for drivers to understand standard signage. If a driver travels through a route that indicates that it is a restrictive route, the vehicle owner will likely receive a penalty charge notice.
Only buses (and, where indicated by signs, other permitted vehicles) can use bus lanes. The definition of a bus contained in the Traffic Signs Regulations and General Directions 2016 is ‘a motor vehicle constructed or adapted to carry more than eight passengers (exclusive of the driver)’. Therefore, a bus must have a minimum of nine seats including the driver.
Permitted vehicles can vary, so drivers should check the signs at the start of the lane or bus only street before entering. Emergency vehicles (on an emergency call or operational manoeuvre) are exempt from these restrictions.