white squares on roads

[Lord Unstone]

What do they mean/? What are they for?
Pairs of white squares in the road, sometimes even on roads in housing estates.

[NORMANTHEDOG]

they are ther to slow you down,instead of humps.

[chas2008]

on main roads i thought they were used by police for measuring a standard distance and calibration of there speedometer systems, or something like that...

[sddsddean]

Urban myth I'm afraid chas. They are called 'node points' and can be painted squares or circles, or sometimes metal road studs (like at pedestrian crossings). They are used by the Highways Agency (on M ways and trunk roads) and local councils to define lengths of road into sections for maintenance works.

[chas2008]

Vascar (Visual Average Speed Computer And Recorder)
Set at a minimum distance of 1/8 of a mile. The trap could be white squares or round markings on the road but could be any fixed objects of a known distance apart. A police officer uses a time recording device to record the length of time it takes a vehicle to travel through the speedtrap, once this has been done it is a matter of calculating time over distance to acquire the vehicles speed. This could even be done from a helicopter or an officer on foot. As this is largely down to human judgement there is a tolerance for the officers reactions. The tolerance is the same at each end of the reading so the reading is thought to be accurate enough for a prosecution. This can be used in conjunction with video for a safer prosecution. It could also be a police officer following in a vehicle using the same kind of system, again distance travelled over time taken, sometimes used with Provida.

urban myth ???

[Paul22118]

You are both correct. HA do use markings for surveying and the police definitely use them for calibration. Depends really which specific markings one looks at.

[Lord Unstone]

I will measure them next time I am in the area. Thanks for the replies so far.