So, what exactly is a yellow box junction?
Box junctions, marked with yellow cross-hatching, were introduced in 1964, the first one being in London. The aim was to prevent traffic from blocking junctions when it could not proceed and thus prevent ‘gridlock’ on the road.
Yellow (and occasionally white) boxes are used anywhere where the road needs to be kept clear. The example below shows a yellow box being used to keep a junction clear.
Normally you will see yellow box markings in towns or busy thoroughfares. The markings can also be found outside the police, fire ambulance stations or hospitals where there is an access to road forming a junction with the main road.
The basic principle that applies to yellow boxes is that you must not enter the box unless there is enough room to exit. It is an offence to block a box junction – the only exception to the rule is explained below.
The diagram above shows a car at point ‘A’ wishing to turn right into road ‘C’. As long as road ‘C’ is clear, it is OK for the car to move to pont ‘B’. In other words, you may enter the box and wait when you want to turn right, and are only stopped from doing so by oncoming traffic, or by other vehicles waiting to turn right. In the diagram below, no one would be able to enter the yellow box because the exits are not clear.