Motorway driving is an everyday activity for most drivers, but knowing what to expect when out on the roads is important.
In this know how guide, we explain everything to do with slip roads – from what the road signs looks like, to how to enter or exit them.
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Slip road
A slip road is a short link road that allows drivers to safely join or leave a faster, busier route such as a motorway or dual carriageway.
They are commonly found across the UK, and are an integral part of the road network.
Drivers will typically find slip roads at motorway junctions, major roundabouts, and service area exits.
They are in place to give vehicles space to adjust their speed before merging with or separating from high speed traffic situations.
Their design helps keep main roads flowing smoothly by reducing sudden braking or congestion.
Speed limits on slip roads usually match the limit of the road being joined, although some have lower posted limits due to tight bends, short merging lanes, or nearby hazards.
Drivers should always pay attention to road signage and speed limits.
They are also expected to follow key rules to the road. This includes building up speed to match the traffic on the main carriageway or motorway, check mirrors and blind spots, signal early, and merge without forcing other road users to slow down sharply.
What does a slip road sign look like?
Here is what a slip road sign looks like on a UK road. This signifies that additional traffic is joining the road from the left on the stretch ahead.
Traffic on main carriageways have priority over joining traffic from slip road - so beware when on the roads.
Different types of slip roads in the UK
Below are the types of slip roads you will see in the UK:
- Entry: Used to join a motorway or dual carriageway. They give drivers space to build up speed and merge with traffic.
- Exit: Used to leave a major road. They allow drivers to slow down away from fast‑moving traffic.
- Tapered slip roads: A short merging lane where the slip road narrows into the main carriageway, requiring confident, well‑timed merging.
- Parallel slip roads: Provide a longer, separate lane running alongside the main road before merging, giving more time to adjust speed.
- Loop slip roads: Curved, often found at large junctions or motorway interchanges, allowing vehicles to change direction without sharp turns.
- Two‑lane slip roads: Wider slip roads designed to manage heavier traffic, sometimes separating traffic by destination.
The roads and accompanying slip roads will have signage, so it is important to adhere to the road rules.
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How to join a slip road
If you are joining a motorway or dual carriageway safely, it begins with using the slip road to build up speed and match the flow of traffic.
As you approach, check your car mirrors and blind spots, and then signal early to show your intention.
You will then need to use the length of the slip road to accelerate smoothly, keeping an eye on vehicles already on the main carriageway, and in your rear view mirror.
Next, drivers will have to position the vehicle so you can merge without forcing others to brake sharply or creating a dangerous situation.
It is important to look for a suitable gap, adjust your speed, and move across decisively when it’s safe.
How to leave a slip road
Drivers looking to leave a major road should start by checking for road signs early, so you know which lane you need to be in and then signal in good time.
You should reduce speed only once you are fully on the slip road, not while still on the main carriageway.
By doing this, it keeps the traffic behind you flowing smoothly, and reduces the risk of an incident.
Once on the slip road, continue slowing to a safe speed for bends, roundabouts, or junctions ahead.
Stay aware of other vehicles that may also be exiting, and position yourself clearly.
Good anticipation and smooth speed control make slip road exits safer and more comfortable for everyone on the road.
RAC sale – up to 40% off*
• Standard cover from £5.29 a month*
• We get to most breakdowns in 60 mins or less
• Our patrols fix 4/5 breakdowns
*T&Cs apply.
*T&Cs apply.
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