After seeimg Tony's estimate of $60 million, I'm inclined to agree. Perhaps some alternative fuel busses running from Palladio to the Historic District might be considerably cheaper and less have less impact on infrastructure.
To make that number a little less scary, we might compare it to the cost of, say, widening E. Bidwell by one lane in each direction for four miles. That would be at least $10M-$15M. And that doesn't include any vehicles.Bottom line is that public works projects are expensive.
There has been lots of debate in recent years about streetcars versus buses, light rail versus bus rapid transit, etc. It is true, but lines have far lower start-up costs, are flexible and can be adjusted to serve demands. The argument for fixed rail is that because of it's permanence and some level of cache that buses do not have (and there is some evidence that the lowly bus is making a comeback, as evidenced by Google buses and a whole slew of new private intercity bus companies, such as Megabus) excepted). People who ride transit by choice are far more likely to ride a train than a bus, whereas transit-dependent folks will take whatever is offered. Compare the ridership on light rail in and out of Folsom with Folsom Stage lines (LRT runs on half-hour headways, Folsom Stage Lines is on half hour or hour, depending on the line and time of day). The other stated benefit, touted heavily by places like Portland, is that the very fixed and permanent nature of rail transit gives it a much bigger economic impact on surrounding neighborhoods - i.e., it has the ability to spur development (no pun intended). One more thing about buses is that they are cheaper because we already spent the money to build the roads they drive on. But because of that, they are at the mercy of congestion, and they add to the damage to the roads (large buses are particularly tough on asphalt pavement because of their frequent stops), which is never included in the "cost" of operating a bus line, just as we fail to include it in our cost of driving our cars.