An 18-year-old Pottstown man has been charged with two counts of homicide by vehicle and five counts of recklessly endangering others for driving his father's Dodge Durango into a guardrail on Dec. 12.

Thomas Andrew Kocon was driving nearly 20 miles over the 55-m.p.h speed limit on Route 100 in Upper Pottsgrove just before midnight when he wrecked the 2003 Durango, according to an affidavit filed today.

He had refused to put the Durango's rear seat down, which kept the four girls riding in the back from buckling their seat belts, Montgomery County prosecutors said.

Three were ejected during the crash. Two of them - Andrea Antonio-Harris, 16, and Breanna Brothers, 15, both students at Pottstown High School - were killed.

Kocon and his other three passengers, including a 12-year-old girl who had been riding on the lap of a 15-year-old girl, were taken to hospitals for treatment.

Kocon's bail was set at $50,000, and he is due back in court Jan. 8. He was still in custody at Montgomery County Correctional Facility as of 6:30 p.m., jail officials said.

Contact staff writer Derrick Nunnally at 610-313-8212 or dnunnally@phillynews.com.