You can now choose between 2 different spline systems for creating roads: Tangent and Bezier handles. Tangent is the system that was already in place, and allows for fast prototyping of a road. 
Bezier handles allows for much finer control over your corners and road control points. So you can first create a road in Tangent mode, and then finetune it in Bezier mode. Or you can just start with Bezier immediatly.

In my opinion the Bezier handles system is much better, but I will keep both systems in for now for further testing. 

How to use
To use the bezier handles: select the curve tool, left click a road point and the Bezier handles will apear. You can then drag the handles to control the shape of the control point.