Relationship between skid mark length and speed of vehicle?

most modern cars don't really skid, braking distance=thinking time+stopping distance. The car will have so much KE which is equal to 0.5mv^2. then using the laws of motion i.e s=ut+0.5at^2, v^2=u^2+2as. you can work out the distance it will travel before the car come to a halt if you know it's intial speed v.