The project was aimed at improving overtaking lane design through a better understanding of driver behaviour during overtaking. Overtaking lane designs and road geometries representative of those found on state highways were re-created in the driving simulator used for this research. Results showed that when the diverge and merge areas are clearly visible, there is little difference between the three different road marking and signage treatments investigated. However, there were significant differences when these areas are not clearly visible. Both the 'new NZ' and the Australian treatments worked well in the diverge area, but not in the merge area. Further research is proposed to investigate the effect of factors such as merge length, merge placement, alternative marking schemes and sign placement.