A Port Authority Police officer was struck by a speeding driver early Tuesday in Jersey City as he was assisting on the scene of an earlier accident, the Port Authority said. It happened around 12:30 a.m. as the officer was putting out flares along the road near Palisade Avenue and Route 139, officials said. He was rushed to a nearby hospital and is listed in "stable" condition although the extent of his injuries is not known currently. Officials said the driver of the speeding vehicle was taken into police custody but no word yet on any charges.