As part of an investigation of accidents occuring during mounting on and dismounting from heavy construction equipment a study was conducted of operator behaviour during mounting and dismounting. Measurements of access systems of representative vehicles were compared with those from various Standards. In most instances the vehicles did not conform. Recommendations are made for improvements in the safety characteristics of the access. These recommendations are in three classes, namely; changes and developments in procedures and practices, retrofit of existing equipment, and changes in design philosophy. The need for maintaining three point contact at all times during mounting and dismounting is emphasised.