Final tests before 20mph restriction is enforced in Wick

DRIVERS in Wick are currently having their speed monitored at various sites in the town in preparation for the planned 20mph restrictions.

The Highland Council recently confirmed that its road safety team requested that the devices, consisting of a monitoring box and two black cables stretched across the road, be put out at various locations.

A council spokesperson said: "They are part of the information gathering process for the proposed new speed limit in Wick plus review of existing limits."

At one side of the road is a sealed box collecting data from two black cables extending from it.

The cables are actually pneumatic road tubes or hoses which have been used for many years as a popular method of vehicle counting.

When a pair of wheels hit the tube, air pressure in the squashed tube activates the data logger which records the time of the event. The second tube is then hit and it also records the time. The small difference in time between the two hits will give an accurate calculation of the vehicle's speed.

The data logger can also establish vehicle direction by recording which tube is crossed first. This has the drawback that if two vehicles cross the tubes at the same time then the direction can't be accurately determined. Should two cars be very close together when they cross the tubes, the system may see them as one multi-axle vehicle.

The counts need to be physically downloaded onto a computer from the loggers at the roadside and there is no information on car registration on the device.

Road tubes work well for short duration counts on lower volume roads. They are not as effective on higher volume, multi-lane highways.

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