Only crashes which occur at or within 20 metres of a junction are coded by Junction Detail. If two or more junctions are present within 20 metres the junction closest to the to the crash location is used.
The following definitions apply to particular varieties of junction:
- T junction includes 3 arm junctions where 2 roads join at an acute angle (sometimes known as 'Y' junctions).
- Crossroads refers to four arm junctions where the alignment of both roads is uninterrupted whatever the angle of the crossing, and the arms are not staggered.
- Multiple junction refers to all junctions with more than four arms, except roundabouts.
'Slip road' only for accidents occurring within 20 metres of the point where a slip road (including filter lane at roundabout - See 1.14 Note F) merges with or diverges from the nearside of the main carriageway.
Accidents occurring on slip roads, within 20 metres of a roundabout should be coded 01 or 02 as appropriate. Accidents occurring on slip roads which are not within 20 metres of a junction should be coded 00.