How public money is spent

Rarely have I seen a more perfect example of the care with which public bodies expend public (tax) money. The Bay Bridge connecting San Francisco with Oakland is a $6.4bn two-span bridge, connected by Yerba Buena Island in the Bay. It has There is already a bike + pedestrian path on the 2km east span (Yerba Buena Island to Oakland). So why not provide a dedicated bike path on the 1.5km west span?

Why not, indeed. Here (from the proponents) is the case for a bike path over San Francisco Bay:

With the east span finally open, planners are already at work on the next mega-Bay Bridge project - a $1 billion-plus makeover of the western span that would include a $500 million hanging bike path.
"I'm sure the bike advocates are going to start agitating for that" soon, Metropolitan Transportation Commission Executive Director Steve Heminger said

I'm sure they are. Since they're not paying for it, why wouldn't they? And who is going to pay for it?

Drivers are already paying up to $6 at peak hours to cross the Bay Bridge. Redoing the western side to include the bike path would probably mean "putting something in front of the voters," - like a "temporary" $1 hike in bridge tolls, said MTC spokesman Randy Rentschler.

Let's do the maths here. Over a 40 year lifespan, assume that the $500M cost is approximately tripled by maintenance (5% per year, which seems optimistic if anything). Looking at weekday traffic of ~ 250 days per year, that's 10,000 days of cycle traffic. Divide $1.5bn by 10,000 and you see a $150,000 / day cost of the bike lanes. Assuming - in a fit of optimism - that 10,000 bikers per day decide to bike to Oakland, over the bridge and along to their office in (notably steep and traffic-snarled) San Francisco, that's $15 per biker per day. Are they going to charge that to bikers? My arse, they are. This, as Rentschler notes, will be going straight onto the tolls of motorists (as they are a captive audience) who will reap less than zero benefit from this extension. But the San Francisco politicos have a Green source of campaigning dollars to appease, and they're in no danger of being voted out, so why wouldn't they do this?

This is a classic destruction of wealth. That $1.5bn of money could easily be invested into a project with a better social pay-off - or even, horror, returned to the voters to spend in lowered state and city taxes. However the bike path is an irresistably visible and "green" capital project for egocentric politicos to attach their name to. There's no way that it's not going to be built, despite the economic insanity of the project.