| All of these are correct | |
| More following distance than driving with a single trailer | |
| More skill than driving with a single trailer | |
| More care when driving in bad weather and on grades |
| 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 |
| Close the shut off valves of both trailers | |
| Open the shut off valves of both trailers | |
| Open the shut off valves of the second trailer and close the shut off valves of the first trailer | |
| Open the shut off valves of the first trailer and close the shut off valves of the second trailer |