Skid marks alone will not give the speed. Since there was a collision, some of the energy was used up to move, and damage the vehicles that would have created longer skid marks. If you know how far and in which direction the cars moved after impact, and each vehicles weight you could get a speed. A more simple approach would be to do a time study. From the begginning of the skid, back the other car up for 1.6 seconds (accepted reaction time) at the speed limit( mph * 1.47= FPS).
thats where the other driver was when you pulled into his lane. now bring him back foward at the speed limit. Take the amount of time in seconds that it takes you to enter the roadway. Would the collision have still occoured? Unfortunatly, no matter how in depth you reconstruct the scene, the question remains.
Sir, if you saw this car, and you saw that it was speeding, why did you pull out in front of it?
If you didnt see it you were wrong, If you did not properly judge its speed, you were wrong.
Good Luck, Stay Safe.