How is this pavement optimized to suppress water splashing?

Question

In my experience driving through the rain at speeds above 100 km/h results in a cloud of sprayed water behind the car, like so:

However, I encounter more and more recently repaired road sections where the pavement is virtually immune to splashing:

Those pictures are taken 10 seconds apart, on the autobahn A5 near Rastatt. I also have a corresponding video, where the exact border between old & new pavement can be seen.

Can anyone explain how new pavements achieve this remarkable performance at eliminating splashing?

What properties help draining water so effectively?

Answer 1

Although I am unsure of the material that is being used for the roadway in your photos it appears similar to Topmix Permeable concrete

You asked

Can anyone explain how new pavements achieve this remarkable performance at eliminating splashing?

Response

Topmix Permeable concrete is simply a very porous concrete interlaced with large rounded pebbles. In order to allow as much water as possible through the roadway and continue to absorb liquid a base of rubble and channels must be formed. They do not eliminate splashing so much as they absorb and allow liquid to drain down through the surface.

Other Technology

The State of California in the US has an initiative of porous concrete solution combined with recycled rubber from tires. Here is a state government technology guide describing the initiative and the technology.

Cost Justification

Drivers of cars can allow their tires to become degraded and wait until the last minute to change them creating a safety issue due to bald tires and what not. The cost to the government for the healthcare of these individuals can be relatively high. A proactive cost control method employed by the state could be to employ this type of road technology to decrease the number of accidents annually. The one time cost of implementation could be less than the cost related to the healthcare of individuals who suffer crash related injuries in the rain.

Answer 2

It's Flüsterasphalt

(literaly whisper asphalt)

@DucatiKiller has already given a nice answer about a concrete version of this, however, this is really asphalt and is also processed more or less like standard asphalt (Lots of heat etc.).

The one and only reason why this is used here in Germany is to reduce the noise of the wheels on the road, and it really makes a big difference, even on a dry road. It seems there's no noise from the wheels any more.

Cars make even more noise on a road with water on it, but this is completely swallowed, too.

Of course, having no water on the road is safer, too: Better visibility (see your pics) and more grip.

That point of @DucatiKillers answer about cars with worn tires was never discussed here.

The draw back of Flüsterasphalt is that the pores will clog up over time with dirt and rubbed-off material from the wheels, so the noise reduction effect doesn't last very long. Another point is that water enters the asphalt and can break it up when it freezes.
It's said that Flüsterasphalt lasts for about 8 years, while standard asphalt lasts up to 20 years.

Near cologne, they used this asphalt a couple of years ago, but next year, they already have to exchange it...

Ah, and by the way: Some cities like mine now start to use it on big roads in the center of the city. But at the low speed limit there, noise of the wheel usually isn't an issue...

Answer 3

I cannot know for sure, but the new pavement may be more permeable than the old, allowing water to quickly drain directly through the roadway, rather than collecting on the surface and having to run off the sides.

See this video for a demonstration