Investigate the effect of different speeds on stopping distances, dynamically - watch the cars slow down and investigate how speed changes over distance (rather than simply over time). Can be used alongside http://www.thechalkface.net/resources/stopping_distances.pdf

If you could stop just in time to avoid a crash when travelling at 20mph, how fast would you be going at impact travelling at 30mph? [br][br]How does this change for 70mph / 80mph, etc? [br][br]Why is this? [br][br]How much of your speed do you lose during the first 3/4 of the distance?