One possible non spherical cow... if deceleration isn't linear, then there's a possibility peak decelerations could differ between oncoming car and "immovable"

One possible non spherical cow... if deceleration isn't linear, then there's a possibility peak decelerations could differ between oncoming car and "immovable" object. And yeah "immovable" isn't literal, just shorthand for practically immovable compared to the car.