Head on speed is very difficult to judge. Have you ever stood next to train tracks and watched one approach on a straight?I knew a guy that was hit by a train while trying to get his dog off the tracks. No one could believe that he couldn't judge the train's speed and get to safety. Well I was waiting to cross tracks next to the beach when a train was incoming and decided to wait for it to pass.It got to me a hell of a lot faster than I would've imagined. Without passing perpindicularlyto a reference point you really can't gauge the speed.