Ice road in Estonia (pretty much what it sounds like: Ice road).
The road is open from 10am until 5pm, and is limited to vehicles under 2.5 tons. Drivers are forbidden from wearing seatbelts (assumedly because of the need to rapidly exit a sinking vehicle).
Most interesting - there is a dual speed limit in place: roughly under 16mph OR 25-43mph. This is to prevent creating a resonance wave in the ice layer which could break the ice.
I think they're trying to avoid something similar to the famous Tacoma Narrows bridge collapse:
Ice sled propelled by saw blade
The Tyrolean Iceman's tools - photos and images