To me it seem reasonable middle ground. You get either 0 degree or 90 degree. That is glancing or head-on. 45 being between is not unreasonable option to set as

To me it seem reasonable middle ground. You get either 0 degree or 90 degree. That is glancing or head-on. 45 being between is not unreasonable option to set as coming at some repeatable angle. As you cannot test all collisions. Head on crashes have already other methodology. Which covers some ground. After all you can only do limited amount of testing.