In the simple ranking technique, routes are segmented based on user-defined length. Performance measures are calculated at the segment level which represents the overall safety status. Therefore, further segmentation (i.e. sub-segments) is not necessary for the simple ranking technique.
An example of simple ranking is described below with the following assumptions:
Consider, 9 mile segment of a network element, say route A. Length of major segment = 1 mile.
Resulting major lengths: 9 mile segments each of 1mile.
Major segments | Start | End | Crash Counts (x) |
1 | 1 | 2 | 0 |
2 | 2 | 3 | 0 |
3 | 3 | 4 | 3 |
4 | 4 | 5 | 0 |
5 | 5 | 6 | 0 |
6 | 6 | 7 | 1 |
7 | 7 | 8 | 0 |
8 | 8 | 9 | 0 |
9 | 9 | 10 | 0 |
If the simple ranking is performed with the Prediction Model, the routes again are segmented based on a user-defined length. Different
performance measures e.g. expected crash counts calculated by prescribed Safety Performance Functions
(SPFs), observed crash counts and any combinatorial crash counts using observed and expected crash
counts; are then calculated at the segment level, which represents the overall safety status.
