State transportation operators this week scanned nearly 50 screens showing vehicles crawling along highways like bugs — bracing for a holiday surge over the next three weeks that almost certainly will bring out drivers who can’t handle mountain winter conditions. The Colorado Department of Transportation increasingly focuses on traffic flow, and surveillance capacity at its Golden operations center has doubled in recent years, with links to more cameras installed along highways statewide. Crews at CDOT’s center can also connect by phone with drivers inside nearly 900 snowplows.