Monitoring skid resistance
We monitor all state highways so that we know if the skid resistance on any section has reached its minimum safety standard. We monitor some sections, such as rail and pedestrian crossings and tight curves, more carefully as they must maintain a high level of skid resistance.
Ways of improving skid resistance include:
- water blasting to expose more of the stone chips
- resurfacing the road using new chipseal or asphaltic concrete.
Measuring skid resistance
We measure a road's skid resistance using a Sideway-force Coefficient Routine Investigation Machine (SCRIM+).
This specialist vehicle is equipped with a range of information-gathering equipment and carries a weighted wheel that moves sideways to the line of travel. The wheel measures the resistance offered by the road surface to tell us how good the skid resistance is.
Every state highway in New Zealand is surveyed like this each year, using the same vehicle with which we collect other pavement and surfacing information.
