well, think of it this way, you wreck a bike at 120 MPH, it's gonna hurt/ probably break somthing at least, there is no possible way to impliment any more safty equipment into a bike, other than helmet, jacket, gloves and leathers, but with a car, you can have much more ( cages, racing harnesses, neck braces ect... ), and in most cases, drivers come out ok, or not hurt that bad even in bad wrecks. not to mention the cost of the equipment/ parts needed to make a car pass 11 seconds, is expensive. can go 11.60 or slower with what safty equipment came on the car and a Snell/ SFI helmet. to go 10.99 I think all that is needed is a driveshaft loop ( along with factory safty equipment ), and 10s needs things like a cage, not shure tho. but really, going any faster than 12s is somthing that is out of reach for many people.