How to calculate a route with specific U-turn permission at stopover waypoint

While U-turn permissions can be avoided globally for a route by using the global setting avoid[features]=uTurns, the behavior can be overridden for each stopover via individually by setting the waypoint option uTurnPermission to allow or avoid.

The resulting route will allow or avoid u-turns at each stopover via waypoint according to the value of the uTurnPermission parameter when it's set, or following global settings if the uTurnPermission parameter isn't set.

curl -gX GET 'https://router.hereapi.com/v8/routes?'\
'origin=52.507079%2C13.396498&'\
'destination=52.507079%2C13.393774&'\
'via=52.506783%2C13.388813%3BuTurnPermission%3Davoid&'\
'return=polyline%2Csummary%2Cactions%2Cinstructions&'\
'transportMode=car&'\
'departureTime=any&'\
'apiKey=YOUR_API_KEY'

The image shows two routes. The blue route has the uTurnPermission option set to allow. The purple route has uTurnPermission option set to avoid at the via waypoint 1.