The Traffic Management Center reports some accidents slowing down traffic around the Twin Cities this evening. But on the first day of a temporary shutdown of highway ramp meters, the evening rush hour otherwise appears as uneventful as the morning rush was. State transportation officials turned off all 430 of the meters used to regulate entrance ramps, to evaluate the impact on driving time and freeway congestion. Despite a smooth morning rush hour, officials say it's way too early to draw any conclusions.