Here in Oslo, Norway they've introduced an "environmental speed limit" during winter. The stated reason is to reduce air particulates, as Oslo is prone to very poor air quality during winter.

So one of the main roads circling the city gets reduced from the 80 kph (50 mph) it was built for, to 60 kph (37 mph).

Boy does it feel agonizingly slow to drive 60 kph on a road built for 80 kph.

Recent years they've reduced the summer speed to 70 kph (44 mph), so it feels slow all year now.

they needed a study for this? Ok its good to get the data so now what?

Also, water is wet.