Heavy traffic from Christmas shoppers encountered an unexpected delay Wednesday night when Redding Police Department set up a sobriety checkpoint on Hilltop Drive north of Dana Drive next to the Mount Shasta Mall. The backup was heavy at times as officers checked for signs of impairment and valid driver’s licenses. Between 7 O’clock and 11 O’clock, a total of 680 drivers were screened. Two were cited for driving on suspended licenses, but nobody was arrested for driving under the influence.