Utilizations by routeId - where does that id come from?

[jschirrmacher]

How do you get the routeId in path /utilizations/{routeId}?

It seems to me, that you need to create a route first, and get back a routeId for it to use this path. Yet, there is no such path, so we should add it.

Alternatively, and I like this idea even more, we could specify the waypath explicitly to get the utilization for. In contrast to the first solution, this wouldn't require a session.