Ring Oslo, speed limit

As of November 1, there is a 60kph speedlimit for the Oslo ring, the roadsigns tell me that this is due to a ‘miljøfartsgrense’…or, a speedlimit to save environment?!?

I also understood it has to do with wintertires with spikes…they cause extra dust particles poluting the air. Lowering the speed lowers the concentration of particles…hmm, guess we’ll have to live with it, until freakin’ March 30 2008…aahhh!