Dual Carriageways & Motorway Driving Guide
Introduction to High-Speed Roads
Dual carriageways and motorways are designed to handle high volumes of traffic at speed. While similar, they have distinct differences:
Dual Carriageways
- Two lanes in each direction separated by a central reservation
- May have roundabouts, junctions or traffic lights
- National speed limit applies (70mph unless signed otherwise)
- Can be accessed by learner drivers with an instructor
Motorways
- Three or more lanes in each direction (sometimes two)
- No roundabouts or traffic lights - slip roads for entry/exit
- Blue signs and road markings
- 70mph speed limit unless variable signs indicate otherwise
- Learner drivers not permitted (except in Scotland)
Joining a Dual Carriageway or Motorway
Approach on Slip Road
Build up speed to match the flow of traffic (typically 60-70mph). Check your mirrors and blind spot frequently.
Identify a Safe Gap
Look for a gap in the left-hand lane. Remember traffic already on the main carriageway has priority.
Merge Smoothly
Adjust your speed to merge safely without causing other vehicles to brake. Signal right if necessary.
Cancel Signal & Check Position
Once merged, cancel any signal and ensure you're not driving too close to the vehicle in front.
Never stop at the end of a slip road unless in stationary traffic. If you can't merge safely, use the hard shoulder (motorway only) and call for assistance.
Lane Discipline
Left Lane is Default
Always return to the left-hand lane after overtaking unless traffic conditions prevent this.
Middle & Right Lanes for Overtaking
Only use these lanes when passing slower vehicles. Never undertake (pass on the left).
Check Mirrors Frequently
Mirror checks should be every 5-8 seconds. Be aware of faster vehicles approaching from behind.
Maintain Safe Distances
Use the two-second rule in good conditions, doubling this in wet weather and increasing further in ice or fog.
Overtaking Safely
Check Ahead & Behind
Ensure you have clear visibility and no vehicles are about to overtake you.
Signal Right
Indicate your intention to move out in good time.
Move Out Smoothly
Maintain or increase speed as you change lanes. Avoid braking during the manoeuvre.
Complete the Overtake
When you can see the overtaken vehicle in your rear-view mirror, signal left and return to the left lane.
Avoid "elephant racing" where two large vehicles overtake very slowly side by side. If your overtake will take more than 30 seconds, reconsider whether it's necessary.
Leaving a Dual Carriageway or Motorway
Watch for Advance Signs
Motorways give 1 mile, 1/2 mile and 300 yard warnings. Dual carriageways may have less notice.
Move to Left Lane
Change lanes in good time, ideally by the 1/2 mile marker on motorways.
Signal Left at 300 Yards
Indicate your intention to leave but don't reduce speed until on the slip road.
Decelerate on Slip Road
Use engine braking and gentle brake pressure to reduce speed to match the new road's limit.
Special Motorway Considerations
Smart Motorways
- Variable speed limits displayed on overhead gantries
- Red X means lane closed - move out immediately
- Emergency refuge areas every 1.5 miles
Breakdown Procedure
- Attempt to reach hard shoulder or emergency area
- Turn wheels to left and exit via left-side doors
- Stand behind safety barrier and call for help
- On smart motorways without hard shoulder, follow same procedure in marked refuge
Never stop on a motorway except in an emergency. If you miss your exit, continue to the next junction - never reverse or make U-turns.