How to map url with previous route name

I have two separate routes parking and Car (not a nested route).

Parking route has dynamic segment like parking id /parking/21 and Car has car name and id /car/ford/12

Router.js: function() {
   this.route("parking", { path: "/parking/:parkingId"})
   this.route("car", { path: "/car/:carName/:carId" })

when transition from parking route to car route, i need a url like (/parking/21/ford/12) without making the car route nested

Either the route is nested, or not. I see 2 easy solution here:

a) Have two different routes, that might re-use a component. So: function() {
   this.route("parking", { path: "/parking/:parkingId"}, function() {
       this.route("car", { path: "/:carName/:carId" });
   this.route("car", { path: "/car/:carName/:carId" })

Not the DRYest solution, but will give you the URLs you want.

b) Use a query param on the car route, e.g. /car/ford/12?parking=21