Checking yourself
There are a few things you can do to double-check your work at dividing intersections that need to be mapped with heuristics.
- The total number of lanes on the entrance segment must be equal to the total number of lanes at the intersection:
- total lanes (intersection) = total lanes (entrance)
- The total number of lanes on the middle segment must be equal to the difference between the total number of lanes on the entrance segment and the number of right-hand lanes on the entrance segment:
- total lanes (intermediate segment) = total lanes (access) - right-hand lanes only (access)
- The number of straight lanes on the entrance segment (i.e. the number of boxes checked for the straight ahead) must equal the total number of lanes on the median segment:
- straight lanes (entrance) = total lanes (median)
If these conditions are not met, the heuristic method may not work as expected and it is best not to enter the lanes for the time being.