We’ve all been there. You’re cruising along the motorway or a dual carriageway when the traffic to your right suddenly slows down. Or you approach a car that’s lane hogging. In those circumstances, is it acceptable to undertake? We’re usually given driving advice that it’s not in the UK, but you might be surprised that there are times when it is.
Here, we’re going to explain everything you need to know about undertaking, including when it is and isn’t acceptable and the penalties you could face if you get it wrong. But first, let’s clarify what we actually mean by undertaking.
What is the difference between overtaking and undertaking?
The difference between overtaking and undertaking is down to which side you pass a car on. In the UK, where we drive on left-hand side of the road and our cars are right-hand drive, overtaking is when you pass a car on the right-hand side. Undertaking is when you pass on a car on the left-hand side.
Is it illegal to undertake?
The Highway Code gives definitive advice on whether or not you can undertake. It states: ‘do not overtake on the left or move to a lane on your left to overtake.’ So that’s it – you can’t undertake. Well, don’t be so sure.
Here’s Highway Code rule 268: ‘In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in lanes to your right. Do not weave in and out of lanes to overtake.’
Sounds contradictory – you can’t undertake, but you can under certain circumstances. Let’s have a look at what those circumstances might be.
When is it acceptable to undertake?
Let’s consider a scenario to assess when it is and isn’t acceptable to undertake.
You’re on a three-lane motorway in heavy traffic. Lane three is packed with cars constantly speeding up and slowing down between 55mph and 70mph. Lane two is more sparsely populated with traffic travelling at a consistent 54mph. In lane one, there’s a lorry every few hundred yards sat on their 56mph speed limiter. It would be perfectly acceptable for those lorries to undertake the slower traffic in the right-hand lanes.
But would it be acceptable for you to move over from lane three to lane one to take advantage of the situation? It depends. If you cut through small gaps in the traffic, probably not. However, if you gradually move across when there is plenty of space to do so, the authorities are unlikely to object. After all, you’re essentially just meeting your obligation to use all the available road space – if there’s most space in lane one, that’s where you should be. That lane one is travelling faster is just an added bonus.
When is it not acceptable to undertake?
There are more circumstances in which undertaking isn’t acceptable than circumstances in which it is. Here are just a few examples. It’s not acceptable to cut through small gaps in traffic to get to another lane that’s travelling faster. If the first car ahead of you has left a large gap to the second car, it’s not acceptable to pass the first car on its left-hand side to get into the gap.
If there’s a car in lane two travelling at 50mph and you’re in lane one travelling at 70mph, it’s not acceptable to undertake that car at undiminished speed. Overtake it on the right-hand side or, if that’s not possible, slow down to a speed at which you’ll gradually move past the car.
What constitutes unacceptable undertaking is, to a large extent, in the eye of the beholder. But here’s a rule of thumb: if an undertake causes another car to brake or swerve, or the driver is startled by the move, it’s not acceptable. Indeed, it becomes a punishable offence.
Can you get points for undertaking?
Undertaking in an unacceptable manner is considered careless driving or driving without due care and attention. You could get caught by a police patrol or enforcement camera or be reported by a member of the public with dashcam footage. The minimum penalty for an unacceptable undertake is three points on your driving license and a £100 fine.
However, particularly egregious incidents of undertaking can constitute dangerous driving. The punishment in such cases can be a fine of several thousand pounds and a multi-year driving ban.
Is it an offence to overtake?
Overtaking is perfectly legal, however doing so under certain circumstances can be an offence. It’s illegal to cross a solid white line or an area of hatch markings in the centre of the road; an overtake that causes oncoming traffic to brake heavily or swerve out of the way would also be an offence.
Overtake under the wrong circumstances and you could be charged with careless driving, driving without due care and attention, or even dangerous driving. The penalty can range from a £100 fine and three points to a driving ban of several years.
Can you undertake on a slip road?
The rules and guidelines discussed earlier in this article apply on any multi-lane road. So, if there is a slow-moving vehicle in the right-hand lane of a multi-lane slip road, it would be acceptable to undertake, so long as you don’t go past at much higher speed. Remember, the point of a slip road is to get up to the same speed as the traffic on the main carriageway and you may have to undertake another vehicle to do so.
Can you undertake on a roundabout?
Passing a slow-moving vehicle on the left-hand side on a multi-lane roundabout can be acceptable, so long as you abide by the rules and guidelines discussed earlier in this article. However, you should exercise a high degree of caution, in case the vehicle on your right makes a late attempt to cross multiple lanes towards an exit.
