Junction codes are only used for crashes which occur at or within 20 metres of a junction. 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 alignments of both roads are 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.