first guess: They haven't gotten UV protection right just yet.

My guess is their nemesis, the snowplow.

it's a Spanish website, presumably an invention from a Spanish company. I wonder if a Norwegian customer said "What about snow?" and all the engineers thought "Oh...".

how do normal speedbumps deal with snowplows?

"Raise Plow" road signs near the speed bump.

This would work for non-Newtonian speed bumps as well, though the first time a plow driver doesn't see the sign, and there's always going to be one who doesn't see the sign, you end up wiping out the speed bump instead of just dinging it.

Maybe you could have protective ridges at the side of the road which would act as hard stops for the plough while staying out of the regular path of traffic?

I'd also be concerned about the effect that widely changing temperatures would have on the viscosity and hence critical speeds. It'd suck to install one in summer, get used to driving over it at 40km/h, then during the first cold snap find out it'd turned as hard as rock.

It's supposed to be like a rock at 40km/h anyway. You're supposed to slow down to 5-10km/h

The point was temperature dependence, not the specific made-up numbers.

The difference though would be minimal at the recommended speeds which is why it probably is not a factor. If they were designed to keep speeds at 40mph then it probably would be.

What's the freezing point? Below the freezing point would be far from minimal?

Driving over it at 5 mph when it was frozen solid would probably be minimal.

Usually the thin small ones are removed in the season, and the asphalt ones have signs. This is the same reason the speed bands/rumble strips are concave not bumps.

City plows also have shock absorbers systems that let them ride the bump, but you do get ice pockets after the obstacle.

And the normal vandel everywhere else.

I think it's only available indoors because it's secretly filled with mayonnaise (non-newtonian fluid.) But on a serious note, it's plausible that whatever they've filled the bump with degrades under temperature conditions outside of what you'd find indoors.

Especially high probability for me is that it's not the fluid inside but the rubber covering it, which degrades in heat and UV to a point that it easily oozes out the liquid inside.

Maybe the non-Newtonian fluid isn't very fluid at all under certain temperatures?

My guess was speeding laden trucks.

It looks like a great MVP, and within car parks would guarantee an almost predictable max load weight.

It's all fun and games until somebody drains your speed bump.