Is it possible to smooth the inner curve of this road which follows a curve path without subdividing or adding a subd modifier?
!(http://merdist.com/A6 No 26.png)
You can smooth the inner curve by using Proportional edit mode or press "O" while in edit mode. Subdivisions of the model will be necessary and depending of the numbers of subdivisions the curve will look smooth.
Here's an example, I used a cube just to illustrate what I'm trying to say. First you have to subdivide it, the numbers is up to you.
After that Grab the line where you want the curve to happen, in this case I picked the one in the middle. Once you have selected the line press "O" or you can find it all the way at the top underneath compositing. You are going to see the option enabled when it turns blue. On the right you can see the various types of scaling. You will have to play around and see which on you prefer the best.
I wanted the curve to happen in the center of my model so I grabbed the middle line then press G + X so it only moves in the X axis from there I played around with it to find the curve that I wanted.
I hope this helped.