The techniques used to carry out Cost Benefit Analysis matter. The techniques taught and used today are designed to skew the results towards the short term. They favour systems that cost less to build but more to operate. When we apply this approach to public transport we get continual road works and resistance to integrated public transport networks involving a mix of transport modes.
If we change the way we do our Cost Benefit Calculations to remove short term bias then we find that an integrated transport system that includes Light Rail gives the greatest long term benefit. We also get fewer roadwork upgrades.
Removing the bias means we have to change the way we fund long term projects away from debt. We can change to the community issuing and benefiting from its own credit. This is called Crowd Funding or getting the users of services to fund the services they will use in the future. This gives users both the benefits of the service and the income from funding. This means that over the long term the total cost of projects like Light Rail come back to the community; including the profits from funding.