Hmmm... I don't know Seattle. If the tax is repealed, will the projects be built anyway? If the floating bridge or the waterfront freeway deteriorate to where they must be closed, does the whole place simply seize up? Is letting them go a serious option?

If the projects must and will be built, shouldn't the tax be raised so at least the user pays, which is almost always sound economics on its own merits?

Maybe you mean to imply that they ought to build transit. But is that a serious option either?

After what happened with the Red Line in Los Angeles ($4 million apiece subway cars and $500 million a mile, could have bought every rider a very expensive car and had great gobs of money left over) is anybody ever going to build transit again in any sort of serious way, despite the cost of freeways?

Look at the lackadaisical desultory 50-year-long non-effort on New York City's Second Avenue Subway. Over those five decades, they bonded it at least four separate times that I know of; they squandered all the bond money on "holding the fare down"; and now they've got countless billions in debt and a grand total of, what, six stations on a line to nowhere? If the country's most transit oriented city has basically only torn down lines over the last 50 years - Third Avenue, Myrtle Avenue, the IRT el in the Bronx - does't that say something? Who can afford to build transit under today's political conditions, and today's rules and regs? Who would ride it if it billed honestly, and charged $5, $10, and more a ride, as it really costs?

The reason mass transit does not work for USA is cheap gas and enormous subsidies to cars in the form of roads, highways etc. The highways are built with federal funds, mass transit is local and that's why it is easy to push a finger - see how uneffective it is... If you calculate the real cost of both in terms of pollution, trafic congestions etc. you will see why every other country with a little more long-term view has invested heavily in it.
Floating bridge - We have only two bridges crossing a 20 mile long lake that lies between most of the area's population and many of the area's largest employers (including Microsoft)  Half-hour delays to cross these bridges at rush hour are the norm now.  I pay 30% higher rent to live on the same side of Lake Washington and consider it a bargain to avoid that commute.  If we lost the 520 bridge a bad commute would become impossible.  I'm not sure if that is a bad thing in the long run...

Alaska Way Viaduct - The concern as I understand it is that it is an old multilevel freeway that might pancake and kill hundreds of people in the next large earthquake.  It needs to be removed or replaced.  

Mass transit doesn't mean just subways.  Buses and light rail, and carpooling require less investment.  
I've been thinking about organised carpooling.
Via mobile devices you just point your start and final destination and you wait for an available driver at designated car-pool stops. The "matching" driver is also notified real time about the people waiting for him/her. The fee is automatically charged on your account and part of it goes to the drivers account.

Imagine what savings in terms of traffic, gasoline, toll road and parking lot fees and added benefits (including increased social contacts) such a system can give. In addition some people can do it for living thus reducing unemployment.

Wouldn't this be simpler?

"It's a Gift" (1923) Snub Pollard plays an inventor with a bevy of Rube Goldberg contraptions. He rides to work in a bullet-shaped vehicle that he propels by using a giant magnet. When a car passes in the direction that he wants to go, he holds out the magnet and away he goes, speeding down the road in his bullet-mobile.

:-)

Nice :)
The technology pieces are all there to do this...on-demand carpooling. It's not Buck Rogers gee whizzery. I've been toying with another developer on a google maps mashup for carpooling, implementing a subset of the requirements outlined at communitysolutions.org. What's missing is the cool factor...that carpooling is as cool as wearing an ipod. If people thought carpooling was cool, the technical pieces could fall into place very quickly to facilitate it.
Frankly, unless you work in a whole lot of security, what you're describing sounds more like hitchhiking than carpooling.  I'd be nervous getting in a stranger's car, and I'd never want my wife to have to do it.
Given that everything will be tracked to the last meter, this is more of an irrational fear like the one you feel the first couple of times you jump from a cliff in the water, or buy things over the internet.
Knowing who killed my wife or daughter wouldn't be much comfort.
I did not get it at first that you fear traffic incident not something else.

Well first it would be a matter of free informed choice, like the one you make going into a bus, taking a cab or jumping into an airplane. I do admit that the idea is pretty weak at this point but my idea is that at some point of time in future we will be forced to try anything that works. And this one definately could work and I may suggest it would work pretty well. It is the perception of "one car, one driver" we are so used to that actually stops us.

FWIW, my wife's daughter and her husband have both started carpooling to work, and there have been articles about that sort of thing in the local rag.  I think that sort of thing will happen by itself.  

In college, I used to post ads to bring anyone back and forth for a given holiday weekend.  That is closer to what you are suggesting, many people do it, and I suppose one could research how risky it is to travel that way.

Busses? Aargh. Yeah, they're cheap, but as they're nearly always run - stopping at every corner - they take all day and all night to get anywhere. Useless. And in newer areas that don't already have dense transit coverage, you'll never get a bus that doesn't stop at every corner past the disability lobby.

Organized carpools? It's not worth taking a chance on getting mugged or carjacked just to save a few bucks. Nor is it worth risking trumped-up sex-harrassment (or assault) charges to save a few bucks. Remember the Great Day Care Witch Trials of the 1990s? Not only that, but even aftrer you solve those two issues, you still have to get past the taxicab lobbies in our thoroughly corrupt big cities. Fat chance; the world owes them a living no matter the cost - look at all the years and years the hacks helped delay transit to Chicago O'Hare and to New York's Kennedy Airport. Fuhgeddaboudit.