When Jaime Sommers attempts a first jump from one rooftop to another, it can be clearly seen that she is wearing high heels, but as she climbs over the parapet wall, her high heels have disappeared.
In the crashing scene, it can be perfectly seen from the camera inside the car that the truck hit the entire side of Will's car. However, in one of the following outside shots, the truck just hits a small portion of it and in a different angle.