I tried this out recently with the new road plates. Because the new system is composed of proper plates with connection points on the underside, this is fairly simple to do. It really comes down to selecting parts that can allow the road to be held in place securely at an appropriate angle.
Here's what I did using plates with clips and handles:
If you were building this for a display, you could get by with many fewer clips, but I was building this with my 5 year old, so it needed to be able to survive significant play. It's held up just fine for us.
Here's the final result with some bricks added to conceal the open sides: