Priority junction and site access junction design.
Priority junctions for site accesses, from simple T-junctions to ghost islands and right-turn lanes, designed to the right standard and tested for capacity.
Also known as: priority junction, site access junction, T-junction design, ghost island junction, right-turn lane
What’s included.
Most site accesses are priority junctions. The design depends on the road, the speeds and the traffic: a simple junction may be enough, or a ghost island or right-turn lane may be needed. Manual for Streets applies on most local roads and DMRB CD 123 on higher-speed routes.
- Choice of junction form
- Geometry, radii and carriageway widths
- Visibility and forward visibility
- Capacity testing in PICADY where needed
- Pedestrian and cycle crossing provision
- Swept paths for the design vehicles
Straightforward, proportionate, agreed early.
Fit the road
We size the junction to the road and the traffic, not to the biggest standard in the book.
Tested
Where queues are a concern, we model the junction in PICADY and show the results plainly.
Walkable
Tight radii and good crossings where pedestrians need them, wider where large vehicles genuinely use the junction.
Questions we get asked
When does a site access need a right-turn lane?
It depends on the traffic on the main road, the turning volumes and the speeds. We test it against DMRB or local guidance and agree it with the council.
Which standard applies, Manual for Streets or DMRB?
Manual for Streets on most streets and lower-speed roads. DMRB on trunk roads and often on higher-speed rural routes. Councils have their own policies too.
Can you model the junction?
Yes, using PICADY within the Junctions software.
Often needed alongside.
Last reviewed October 2026 by Ripple Development Planning. Policy and guidance change; for advice on a specific site, send us the details.
From our insights.
Need help with priority junction design?
Send us the location and what's proposed. We'll tell you what it needs, with a fixed fee.