Car manufacturers are considering things like this, though the systems are by far not good enough and widespread enough yet to be safe.
Some stuff works, but others fail.(like the Mercedes Pre Safe braking system)

Mercedes Pre Safe:
http://youtube.com/watch?v=6nNf1ceiJZc

I like your idea of using markings on the roads for the cars to calibrate on. We used to do this with little Lego Mindstorm robots at uni and held competitions. (Shameless bragging ;P : I hold the all time autonomous robot racing track record at my uni, i used exactly this concept of calibration using dark and lighter spots on the racing track.)
You know what's weird though, when i wrote the calibration software it worked perfectly on the robot i always worked with, but failed on other robots which were supposed to be the same, but each sensor and laser is slightly different even though it's the same brand and has the same specification etc, so the software needed to be slightly rewritten for other robots, as their sensors where sometimes maybe more or less sensitive and their lasers more or less bright.
This problem might also occur with cars, but it's a problem that can be worked around i guess by making higher quality sensors, lasers, radar etc.
Also maybe even autonomous learning calibration systems that adapt to the exact sensor, lasers and radar could be developed in the future. If this doesn't happen your garage might have to recalibrate the systems in your car everytime you bring it in for a check-up, but i guess it's not much of a problem, because they already do somewhat similar things to align the wheels of your car.

Anyways i still think there are many things to be resolved. To name a few examples. In France there was this guy who turned on cruise control in his Renault on the high way, but he wasn't able to turn it off.
They had to clear the high way 60KM in front of him because he couldn't stop.

In The Netherlands there are autonomous driverless robot busses without drivers called parkshuttles.

Parkshuttle:
- http://www.carfree.com/cft/i033-480.jpg
- http://www.2getthere..._parkshuttle-1_2.jpg

They work perfectly when the computer system does all the work, but as soon as a human tries to intervene with the system it fails.

Parkshuttle crash:
- http://tweakers.net/...i.dsp/1133878146.jpg

Also BMW has a system where the car finds an empty parking spot and then drives itself to the parking spot without the driver in it. I haven't heard anything wrong with it yet, but i imagine it can create problems.

BMW finds a parking spot and parks itself:
- http://youtube.com/watch?v=fNtSl3SHnCE

its far too complicated! and am sure car comps are breaking there head to find a god tech! the night rider style :)

Since automatically driven cars are already being researched, what's missing isn't the hey-wouldn't-this-be-nice thought, but rather a biz model.

two words: public transportation.

currently technology that allows cars to drive on there own require special magnetic pins drug into the pavement. it's expensive to do and not very reliable.

unoriginal...big companies are on this..wat h discovery channel.

If you are looking for feedback if it is a good idea... it is.

However, car companies are already tackling it...

So you would need a business model to sell me on it and get more stars.

simple and safe solution is to plan your night out drinking - take a bus or find a friend that does not drink to excess.

I thought its a CAT Chaffeur! lolz...but this is a true wishful thinking than a crop of social sites pulling my friends' time.

5 stars!

There is a service that I know of that will send a tow truck to pick you and your car and bring you both home safe. Just for this.