Agreed regarding absolute value, my usage of differential is not comparing different scenarios but focused on one. So 25 mph + 40 mph in a 25 mph is dangerous.

Agreed regarding absolute value, my usage of differential is not comparing different scenarios but focused on one. So 25 mph + 40 mph in a 25 mph is dangerous. 80 mph + 55 mph in a 55 mph is dangerous. Obviously the former has much less energy, but within itself, the differential is what creates the most accidents and danger.