That's simple, and I've actually done it. I live in Wakiki and work at UHWO. By car, at a minimum it takes 1.5 hours round trip. I fill up with gas every 4 days. The schedule for rail would be a train leaves no more Han every twenty minutes and the ride along the entire length will be a half hour. Increased demand can be easily met by adding trains to the route, and it's automated. Bus service is now crippled, like car transit, by traffic congestion. The environmental impact statement has a whole section on this. On time arrivals are declining, routes take longer, and the buses burn more fuel. Thereby increasing costs and fairs. Having an integrated commuter system with rail as part of the networks proves the whole system. OTherwise forget about the bus it's doomed under current circumstances.  My calculation as to savings on my commute was $2,000 a year. That didn't include the car payment.