KB10442 - Does the DK support turn restrictions? Can costs be associated with turning, so that, for example, a left turn costs more than a right turn?

The DK supports the blocking of specific turns in situations in which one-way or traffic forbidden streets are involved. So a left or right turn into the wrong direction on a one-way street would be restricted in the route calculation. But restrictions must be based on the attributes of links (vector line segments).

Beyond situations involving one-way streets, the DK does not support the assignment of turn restrictions and turn "costs" to the actual intersection nodes. Because the DK is grounded on the concept of intersection nodes, however, a DK developer can customize the DK to support node based turn restrictions. (Or TatukGIS could be hired to develop this functionality). In order to program costs/restrictions directly to the turn itself, the DK would need to be modified so as to consider the spatial relationship between two touching links and the “history” along the route. As an example, the program would need to recognize that a given route involves a course first via node 56 to node 57 and then to node 588, and recognize from the spatial relationships of vector segment 56-57 and vector segment 57-588 that such route involves a left turn. Then the restriction or cost factor can be assigned to that situation by appropriately coding the cost information to the attributes of the vector line segments involved.