
## 4.2 The Exposure Detection Method

At each second, in each zone of the intersection, groups of road users are detected, the origin of moving groups in conflict zones is identified, and the durations Z, X, Y and Ym are updated following the algorithm 5.

Algorithm 5. The method for the detection of exposure.

if at least one group of road users is crossing the conflict zone from approach A (respectively B)
Z(A) (respectively Z(B)) is incremented if there is at least one group of road users in the cross-traffic approach B (respectively A)
Y (A) (respectively Y (B)) is incremented if one of the close groups of road users in B (respectively A) is moving Ym(A) (respectively Ym(B)) is incremented else X(A) (respectively X(B)) is incremented

![0_image_0.png](0_image_0.png)

In each example in Figure 3, a group of moving road users is detected in the conflict zone (corresponding to the connected components constituted by 6 and 4 grid units in state "Moving Presence"). In the middle and right examples, groups of road users are detected in the cross-traffic approach: a critical situation is thus identified and Y is incremented. Some close road users in the cross-traffic approach are moving in the middle example, hence it is counted as Ym, while all road users in the cross-traffic approach are stationary in the right example.