Another idea: You could also offer plus/minus buttons in the route view, which restricts the view of the overview to the selection. Similar to the function add roadblock. In addition, show the data, show route / time.
Completely display on the first call.
Then plus button only marks section from curretn position to next via-point (i guess shaping points should not be relevant). Plus-buttons extends llike the function for blocking roads.
Minus-button shortenes again.