The road tool consists of two main parts - a front-end that allows to create the vector paths, and a back-end that applies the definitions when the terrain is generated. Roads aren't separate objects in the engine, they are integrated into the procedural engine, and as such they produce roads that are seamlessly integrated into the terrain. All markings are generated procedurally as well.
1. Will there be a tool to make multi lane one-way roads?
Multi lane roads are just wide roads with proper markings. At the moment the engine comes with just a couple of markings that are encoded within the road-applying shader. The markings will be later fetched from a separate external definition file.
2. Will there ever be a bridge tool or an elevated road tool?
Yes. There will be a procedural generator for the bridges. The same generator is probably going to be used for railway tracks.
3. Is there an automatic intersection snap that will have road markings.
Not yet. It's not just about the markings, the road snapper has to be able to join roads in various conditions - at an angle, slope etc. The markings are the least of the problem.
4. Will there be a highway tool with a barrier wall in between?
The barrier wall (and crash barriers on the sides) could be probably generated using the same generator as for the bridge segments ...
5. Will there be artificial intelligence for the computer drivers in the game?
That's game-specific, but I can imagine that games will use the vector data of the roads + some AI to run around the obstacles.
6. Can speed limits be implemented for different sections of the roads?
Game specific. Hmm, the only relation to the engine itself would be if the engine allowed to attach some custom info to the road nodes, that can be used by the game running it. That could include other traffic-related information too.
7. Will there be a sidewalk integration?
Sidewalks can be done as part of the road. Roads are defined also by their profile shape, which allows to generate dirt roads. One can use a profile that includes sidewalk just as easily. Probably will need to extend the material set to have a different material for the border.