The peel and stick material is all straight. The curve would require cutting slits along the edges to permit the curving. Then patching those.
Scenic express highways
Woodland Scenics system uses edge tape to create the road area, which is then filled with a plaster type road. They have nice dry transfer roadmarkings.
Many I have seen here use mdf cut to shape then color, weather and stripe.
I think you are out of luck for a plug'n'play product. Roads are like mountains, it's your own artwork with several ways to achieve the result.
Here is the EZ-Streets inside of a FasTrack 036 half-circle. When one considers the time and materials cost to model a road, this product will look good and you can run stuff on it. Thanks to Mixy for including this library in the 9.30 release of SCARM.