You can use the Vehicle Stop-over qualifier to specify that a waypoint is meant to be used for stopping for picking-up or dropping-off. This ensures that the calculated route won't begin or end on a road that is unsuitable for pickup and drop-off (for example, a highway or tunnel).
Example use case
Consider the situation where a surface road crosses over a road inside a tunnel. If you were to specify a waypoint located where the two roads intersect (as seen on a map), then the resulting route would begin or end on either the surface road or the tunnel. This presents a problem because you can't stop in tunnels to make pickups or drop-offs.
If you want to use the waypoint for a pickup or drop-off, then you could set the
vehicleStopover field, which ensures that the resulting route begins or ends
on a road that allows pickups and drop-offs (that is, on the surface road).
Example
The following example demonstrates how to set the
vehicleStopover qualifier.
{ "vehicleStopover": true, "location": { "latLng": { "latitude":37.419734, "longitude":-122.0827784 } } }