For some time now I notice that on major roads and highways every 500 metres or so there is a pattern of 'grooves' on the road surface - obviously cut in and then backfilled with liquid bitumen but you can easily make them out.

They look very similar to the 'pressure pads' as you come up to traffic lights but are nowhere near intersections or lights. On my way back from Bris this afternoon there they were, and I checked them on the odometer as 500m spot on. I've started to see them all over the place. Are they there to count traffic flow? If so where are they connected to and where? Do they mark the lids of pits full of spikes? Have they been put there by aliens to follow our migration patterns for when they use us as a food source?
I'm intrigued. Forget crop circles and the Nazca designs this has got my attention.
Are there any civil engineers on the forum who can advise?

They look very similar to the 'pressure pads' as you come up to traffic lights but are nowhere near intersections or lights. On my way back from Bris this afternoon there they were, and I checked them on the odometer as 500m spot on. I've started to see them all over the place. Are they there to count traffic flow? If so where are they connected to and where? Do they mark the lids of pits full of spikes? Have they been put there by aliens to follow our migration patterns for when they use us as a food source?
I'm intrigued. Forget crop circles and the Nazca designs this has got my attention.
Are there any civil engineers on the forum who can advise?