I think what you are referring to is an updated version of Disneyland's people mover:
An elevated system of tracks and autonomous small vehicles. In your vision, each vehicle can be summoned on-demand, pick up the rider(s), travel through a completely computerized grid system that minimizes any potential traffic jams, and deliver the rider to an area near their end destination.
Um, yeah... Idea's like that died when this country stopped doing great things like building the Interstate highway system, the National Park system, the Internet and going to the moon. About 1970. About the same time the government allowed TeeeVeee networks to charge for their news cast programming...which in turn corrupted how Americans received their pertinent information.
...but for your viewing pleasure, we can reminisce about how great we could have been:
Um, yeah... Idea's like that died when this country stopped doing great things like building the Interstate highway system, the National Park system, the Internet and going to the moon....
Which is why we're stuck with what we had in the 70's. Must find a profit motive in it to get private industry to build it because if we wait for gov't it will never happen. Instead we get car makers building overpriced electric cars with very short range that people will only buy because of gov't incentives. That may help the environment (questionable) but does nothing about gridlock and shortage of parking. While I'd rather not see gov't involved, what if some of the money wasted on alternate fuel vehicle incentives and widening freeways went to such a transport system.
Even if it's a government project, though, there has to be a business case. A large dam in the middle the Nevada desert paid for itself quite well, as an example. A transportation system must have a payback from fares or increased tax revenue.
A system to replace cars would not cause builders to develop more quickly or (I think) cause people to buy more houses. The state would lose registration fees, sales tax on vehicles, gasoline taxes and auto dealer tax revenue if your system were to take hold. What revenue would be generated to offset the losses, plus pay for the infrastructure investment and ongoing maintenance?
There are some things we do without a clear ROI, such as the space program and some would argue it didn't pay off well, but most times there needs to be a give to get.
With more than 9 million tourist coming into the state every year, Total direct travel spending in California was $102.3 billion in 2011, a 7.6 percent increase from 2010 spending. Travel spending in California directly supported 893,000 jobs, with earnings of $30.4 billion. Travel spending generated the greatest number of jobs in arts, entertainment and recreation (221,000 jobs), and accommodations and food service (523,000 jobs).
30 Million visit Nevada each year (But 10 Million of those are from California)
I just did some quick ROI numbers on a High Speed (TGV like) route between L.A. - Las Vegas -Tahoe - San Francisco.
Assuming each leg cost $6 Billion, or $24 Billion total. The paid ridership at each station would need to be 30,000 per week @ about $130 per leg. This would be a walk-up ticket.
Break even on a no interest loan would take about 25 - 30 years. Useful life would be about 75 years. Realizing that ROI would be child's play for a co-state industry that captures in excess of $150 Billion/year. One could easily forecast double the revenue and jobs within 12 years if the underlying transportation infrastructure is available.
Problem is that I am using the $6 Billion per leg construction cost. That is the price for a private sector build. If the government does it - triple that.