Corrugations Corrugations are the most likely obstacle you will encounter when travelling. They vary greatly but can make for a very uncomfortable ride if your not educated on the correct driving technique.
There are 2 issues to help make a more pleasant journey. First suspension is the major factor, a quality suspension system will allow you to sit on a speed generally about 60-65 k/ph to float across the tops of the corragations.
Secondly Tyres, a good quality tyre on a medium to large 4x4 (Prado to Patrol) loaded you can deflate tyre to 25-PSI this allows more flex which smoothes the ride and reduces the risk of punctures as the tyre will flex (mould around) the obstacle.