L.A. is Plasti-Dipping their streets.

[RedDevil]

Both tarmac and concrete trap heat as they have a thin film of stagnant hot air over them.

Our highway surfaces are mainly and increasingly paved with a kind of pervious concrete called ZOAB for Zeer Open Asfaltbeton (very open asphalt concrete).
The main goal is to prevent spray and standing water during rain, and that works really nice like this morning; medium rain, no spray, 100% visibility, wipers on short interval.
Over bridges there are small sections of 'regular' tarmac; so the cars throw up spray there and my auto wipers flick into high gear.

The very open structure prevents the air film to form like it does on regular road surfaces; it vents itself so it does not get as hot and the open structure creates small sunny and shaded areas, further increasing convection.
As a bonus, it reflects less than any other road surface.

Such a pity that it is relatively expensive and not very resilient.

[Frank Lee]

Meanwhile in Duhmerica, DOTs are busy cutting rumble divots into every fog and centerline. Holds rain. And rocks. Both of which get thrown onto my windshield. Well Gee, how else are we gonna know where the middle and the sides of the roads are while texting?

[jamesqf]

Originally Posted by RedDevil

Our highway surfaces are mainly and increasingly paved with a kind of pervious concrete called ZOAB for Zeer Open Asfaltbeton (very open asphalt concrete).

Wouldn't that crumble to bits during the first winter? Water seeps into the open spaces, freezes, expands, and there goes your road :-(

[RedDevil]

Originally Posted by jamesqf

Wouldn't that crumble to bits during the first winter? Water seeps into the open spaces, freezes, expands, and there goes your road :-(

It takes almost twice as much road salt to prevent that. Twice as much as ordinary tarmac requires that is.
Yup, it is cumbersome. Still worth it.

[Xist]

So, cars rust twice as fast?

[RedDevil]

No, to the contrary. The salt does not get sprayed around as much as on regular concrete.

[jamesqf]

Originally Posted by RedDevil

It takes almost twice as much road salt to prevent that. Twice as much as ordinary tarmac requires that is.

Must not get very cold there, then.

[RedDevil]

Originally Posted by jamesqf

Must not get very cold there, then.

Not that often, but it does at times.
When it gets really cold it is usually due to dry Siberian wind.
If it does snow under those conditions then they'll mix sand with the salt or use pure sand.
I've seen them spray stuff I don't really know much about; polymers with orange or purple dye mixed in. Maybe as a gelling agent to prevent the salt from washing away too easily.

I did not want to jack the thread btw, I just wanted to point out one way of reducing excess heat in road surfaces.

Come to think of that, LA could mix white stones, sand, crushed glass, shells and/or chalk in with the tarmac to make it lighter in color, yet more durable than Plasti-Dip. What stuff do they use for road markings anyway?