How to show an approximate location along a route on a map?

A pin on a map is a very precise thing, that is the impression it gives. To show that a location is approximate, we can put a circle around it since the error range is in 2D, and that is easily understandable.

I'd like to know how to show an approximate location along a 1D route. Let's say we want to show a taxi or delivery van arriving along a route, the way it's done is by having a pin in the shape of a vehicle moving along the route. Again, this gives a very precise indication of the location of the vehicle.

Let's say we'd like to show the user that the vehicle could be in an approximate location:

A-------=====----B

So the vehicle could be anywhere in the "=" region.

How would we show that in the most intuitive way? I haven't seen any examples of such UX before.