| Nothing | |
| You`ll see the emergency valve open and release air | |
| You`ll hear air escaping from the open valve | |
| You`ll see the brakes on the last trailer engage |
| Another name for rearward amplification is the crack-the-whip effect | |
| The rearmost trailer is the most affected | |
| The longer the trailers you`re pulling the larger the effect | |
| The more trailers you`re pulling the larger the effect |
| Good drivers shift their attention from side to side and near to far | |
| At highway speeds you should look ahead one-quarter mile | |
| All of these are true | |
| Many drivers don`t look far enough ahead when driving |