Merging and lane changes
Merging using the zip method and good queue driving ensure even flow and fewer conflicts at lane drops, roadworks and ramps. Principles are predictability, communication and speed matching.
For signs and signals at roadworks, see Work zone signing .
What is the zip method?
Two lanes merge by letting one car from each lane go in turn at the end of the closing lane. This maximises capacity and minimises stop‑and‑go waves.
| Element | Correct practice | Common mistake |
|---|---|---|
| Positioning | Use the full lane to the marked end | Early, unnecessary lane changes |
| Order | Merge one‑by‑one at the end point | Forcing and double‑merging |
| Signal | Early indicator and clear trajectory | Late or missing signalling |
| Speed | Smooth low speed matching the flow | Sudden accel/braking |
See also Interaction in traffic .
Queue driving: core principles
- Keep steady speed and avoid jerky inputs
- Maintain following distance to dampen waves; see Speed and distance
- Look far ahead and plan lane changes early
- Use indicators consistently; communicate with brake lights when slowing
- Do not block on‑ramps; facilitate safe merging
- Spot sirens early and keep an emergency corridor clear in standstill traffic; see Emergency corridor in queues
Merging in different situations
| Situation | Recommended behaviour | Tip |
|---|---|---|
| Roadworks/lane drop | Use the full lane and merge at the end | Watch for sign 530 Merging |
| Crossing flows | Prioritise flow; avoid unnecessary lane changes | Read the traffic picture early |
| Motorway on‑ramp | Match speed and merge into a gap | See Motorway driving |
Safety and consideration
- Do not brake for “priority” – flow first
- Give space to vehicles needing wide turns, like heavy trucks
- In poor visibility or low grip: increase gaps and merge with extra margin
For give‑way and lane‑change rules, see Right of way and roundabouts .
Common myths
| Myth | Fact |
|---|---|
| Early lane change is more polite | Use the full lane and merge one‑by‑one at the end for best flow |
| Indicators are unnecessary in queues | Indicators add predictability and reduce conflicts, even at low speed |
| Squeezing in before two cars is fine | Zip is strictly one‑by‑one; forcing creates braking and risk |
See Lane signs and arrows . For eye guidance, read The 5 see‑rules .
Pre‑merge checklist
- Read signs early and select the correct lane
- Keep steady speed to the end point, avoid unnecessary stops
- Use indicators and create a clear opening for one car – one at a time
- Check mirrors and blind spots; see Positioning and driving technique