According to one motoring survey, eight in 10 drivers have struggled to get through some yellow box junctions without coming to a halt, and 46 percent have been accidentally caught in one.
Drivers who get caught could face a fine of up to £130.
Yellow box junctions are areas hatched with yellow lines. In general, motorists are not permitted to stop in these areas. They are essentially large "keep clear" signs.
For yellow box junctions to be kept clear, drivers must ensure there is sufficient space ahead before moving into a yellow box junction.
In a minority of yellow box junctions you may be able to pause for a moment before taking a right hand turn. But in most cases, you must wait until there is space to move out of the yellow hatched area.
It's important to read the road ahead and not simply follow the vehicle in front.
If you move ahead without enough space in front, you may find yourself in "no man's land", located after the traffic light (so you do not know when it has changed) but before the yellow box junction. Or, you may find yourself stuck in a pedestrian crossing area, or the yellow box junction itself - neither of which are permitted.
With the lights on green, as you approach a yellow box junction it is important to slow down to ensure the vehicle ahead has cleared the box junction, giving you enough space to move into the next stretch of road. If you are turning, be sure to look into the road ahead to ensure there is enough space.
Waiting to ensure there is sufficient space in the road ahead may frustrate drivers behind you. Try to ignore them if they honk their horn, and wait for a safe space to move into.
You should follow the same rules when using regular junctions without yellow hatching.
You may be handed a Penalty Charge Notice (PCN) if you stop in a yellow box junction. This is more heavily enforced in London and Cardiff, where Automatic Number Plate Recognition (ANPR) cameras have been set up at yellow box junctions. PCNs of £65 are issued for contraventions. This is doubled to £130 if not paid within two weeks of receiving the notice.
TfL data shows that 123,071 PCNs were issued over the last financial year in London, up from 108,164 the previous year.
In Cardiff, about 24,000 PCNs were issued for yellow junction box contraventions, along with nearly 50,000 penalties for 'no turns' or 'no entries'.
For complete information on the safe usage of yellow box junctions, consult Highway Code rule 174.