When and if the city Department of Transportation Services begin its testing on Adaptive Traffic Signal System on Oahu streets and discover that traffic can be speeded up and travel time reduced, there won't be a need for rail.
If the city DTS ever find the time to remodel some city street intersections that stops traffic to allow vehicles to make a left turn into a new intersection design the Federal Highways Administration  recommends, a lot of time could be saved eliminating left turn waiting time.  Lots and lots of time is wasted every single day in intersections with a left-turn arrow from stops to allow vehicles to make a left turn. The new intersection design allows vehicles making a left turn to turn left simultaneously with thru traffic moving forward - thus speeding up traffic and reducing travel time.