Accident cluster site selection criteria
Stage 1 - Site selection
Sites that meet the following criteria shall be designated cluster sites.
|
|
Minimum
number of
injury
accidents |
|
Minimum
number of
KSI injury
accidents |
|
Junction |
5 |
Including |
1 |
|
Junction |
6 |
OR |
3 |
|
Length |
|
|
|
|
100 metres |
5 |
Including |
1 |
|
100 metres |
6 |
OR |
3 |
|
200 metres |
7 |
OR |
3 |
|
300 metres |
8 |
OR |
4 |
|
400 metres |
9 |
OR |
4 |
|
500 metres |
10 |
OR |
4 |
|
600 metres |
11 |
OR |
5 |
|
700 metres |
12 |
OR |
5 |
|
800 metres |
13 |
OR |
6 |
|
900 metres |
14 |
OR |
6 |
|
1000 metres |
15 |
OR |
6 |
|
1100 metres |
16 |
OR |
7 |
|
1200 metres |
17 |
OR |
7 |
|
1300 metres |
18 |
OR |
8 |
|
1400 metres |
19 |
OR |
8 |
|
1500 metres |
20 |
OR |
8 |
Stage 2 - Scoring
Once sites have been selected (using the above criteria), a score is attributed to each junction or length. For a junction or 100 metres length of road the score is simply the number of fatal accidents times 4 plus the number of serious accidents times 3 plus the number of slight accidents (4*Fatal + 3*Serious + Slight).
For longer sections or road the score is calculated usng the following formula:
(4F+3Se+Sl)*(6/(5+L))
(F = Fatal, Se = Serious, Sl = Slight, and L = Length of road in metres divide by 100)
This gives the same score, for example, for a junction with 6 slight accidents and a 1500 metre length of road with 20 slight accidents, as per the criteria above.
The score is used to prioritise the sites, with the highest scoring site having the highest priority.