I got a 4.
http://www.colblindor.com/farnsworth...r-vision-test/
^ This is the same test, but this one actually gives you a breakdown of exactly what type of color-blindness you have.
I actually administer a version of this test in the office quite a bit. It is a requirement for RCMP, police, and various other professions, to pass it.
As for driving. The hues in the Colors on the traffic lights are designed so that people with color blindness can distinguish them.