Monster's task to make our roads safer

It may boast a body like a refrigerated truck and a name like a front row prop, but the Scrim is really quite a sensitive and sophisticated individual.

The Scrim, more fully known as SCRIM+ or Sideways force Coefficient Routine Investigation Machine, is a road inspection vehicle belonging to the New Zealand Transport Agency.

It passed through Masterton yesterday on the first leg of a two-month nationwide tour covering 11,000 kilometres of state highway.

NZTA state highway Wellington operations manager Mark Owen said the Scrim's main function was to check the friction or "skiddiness" of the road surface to ensure it was safe for braking and turning. It did this by spraying water on the road in front of a free-turning wheel underneath the vehicle - a wheel which was then monitored for movement.

"The data from the machine can show us where there are issues with the road surface that could lead to braking issues or skidding," Mr Owen said.

"We can then nip those problems in the bud and reduce the risk of skid-related crashes by making sure we resurface those roads before the surface becomes a problem."

Data from the Scrim, for example, indicated sections of the Rimutaka Hill Rd where "skid resistance was at or below threshold levels for safety", giving those areas priority for resealing.

The Scrim will travel both sides of New Zealand's 11,000km of state highway, driving at speeds between 45km/h and 80km/h, so Mr Owen asks drivers to be patient. It will pull over to let vehicles pass.

The Scrim's equipment includes 20 lasers to record the sideways surface profile of the road, including the depth of any ruts.

The longways profile of the road, which affects roughness of the ride, is measured with two further lasers front and back.