Yaw - Striations
With the advent of ABS braking systems the importance of the angle of the striations in tire marks took on a whole new meaning. The latest information regarding identifying yaw marks and the presence of braking indicates that the striation angle will increase to approximately 45 degrees when vehicle braking is active while in yaw. This is in contrast to the average 20 degree striation marks found in yaw marks when there is no braking involved.
One should also check any striation marks left by rear tires. As these tires are fixed and can not be steered they will show the orientation of the vehicle and thus the vehicle slip angle. With the front tires there will normally always be some degree of steer angle as it takes between 10 and 15 degrees of steer to initially put the vehicle into a yaw situation. Even so, the combination of side slip and steer will normally be some amount less than the 45 degrees found when braking is present.
Yaw - Striation Angle Measurement