On geometrically substandard vertical curves, post spacing should be reduced so that:
- on roads where the traffic volume is less than 1,500vpd, the top 300mm of at least three posts will be visible to approaching drivers; and
- on roads where the traffic volume is greater than 1,500vpd, the top 300mm of at least four posts will be visible to approaching drivers.
A driver eye height of 1.1m should be used to determine the appropriate post spacing.
