PEOPLE driving around the area might have seen this rather curious-looking big yellow machine, with a man walking in front and one behind with traffic warning boards.?The vehicle working along the A377 was from WDM Limited based in Bristol, surveying the structural condition of A roads for Devon County Council’s Highways Division, checking for deterioration since the previous survey.

A spokesman for WDM® explained that travelling at a constant 2.5 km an hour the vehicle drags a beam on the 4.4m road surface between the front and back wheels.

As the beam passes over the road surface between the wheels, the road temporarily flexes a little due to the weight of the vehicle.

This flex is measured to an absolute of one 10th of a millimetre, (less than the thickness of a human hair), the degree of flex can indicate the residual strength of the road and indicate structural deterioration.

This machine was carrying out a deflectograph survey, and measures the structural condition of road layers, this enables a reliable estimate of the residual life of a flexible (Bituminous) road.

?This means the measurements reflect not just visible weakness at the surface of the road but also any developing deep within the road.?

This survey is procured by Devon County Council Highways Division, the information is used to target failing roads and as a design tool so that works can be targeted in the right places for attention, this mitigates the need of digging to check and reduces the impact to road users.

Devon’s A Class roads are designed for 20 years plus and WDM surveys approximately 400 km a year in Devon.?

Last week they began on Sunday in Exeter, went through Crediton drawing a few folks out of their houses to see the rather curious looking (and sounding) machine, the survey machine continued on to Copplestone and the B3220 junction.

WDM is also checking different A roads around Barnstaple including part of the A39 this year.

?A spokesperson for WDM said: “We ask drivers to be patient when they come across this vehicle. The workers walking beside it with their ‘Stop’ and ‘Go’ signs are looking after your safety.

?“It does not usually take more than a couple of minutes for them to be sure it is safe to overtake, please think of them doing their work to help the roads you use,” he added.

?WDM ® is a world leader in delivering safer road surfaces, is also the UK’s largest survey contractor, serving all UK Government agencies and the majority of local authorities, and continues to develop road condition monitoring technology, set new industry standards and help clients and partners in the UK and overseas, achieve new levels of best practice in road safety.?