Roads V2 and V3 versions

If Roads are a consideration:
1. Level 1 roads : Offer X% speed improvement. Any belt/pipe going above it conforms to usual truck restrictions (large sized trucks cannot go over it)
2. Level 2 roads : offers improved speeds and allows players to construct a single layer of under-road pipes or conveyors. Reduced throughput perhaps?
3. Level 3 roads : Can raise roads by as much as 3 levels, meaning 3 layers of pipes or conveyors can be below this raised road. This is basically a highway. Needs a start and end location (under which nothing can be constructed), unlike earlier roads which can be constructed anywhere.
As a special consideration: Long distance Bridges for faster transport (like for curved islands) - but maybe this suggestion is bit of an overkill perhaps?

Just thought of something better - underground tunnels as V4 - similar to highway, but just under the ground

What if your roads were just a materials like asphalt that's dumped on the ground or they could be done like current walls.