Why dont I see cars on my RHW

[Ebeneezer 0]

Why dont I see cars on my RHW? But I see them on all other roads

[nos.17 5,265]

This could be due to a few reasons. Firstly, make sure the RHW provides a viable route for sims to use to commute. If there are no entrances or exits then it will remain relatively unused.

Also, most users (and I am assuming you too) do not place RHW networks directly adjacent to zones. It may be a little confusing, but the cars (called automata) that you see on roads are not actually real; the simulator is using them to represent the fact that there is traffic on that network. Any RCI zone adjacent to a road, street, rail, etc (pretty much any network) will spawn these visual vehicles. If you have no zones touching the highway or no sims traversing it, nothing visual will appear.

Note, however, that there are artificial ways to get cars to appear on roads: traffic generators. You may want to check them out (there are a few out there).