An off-duty SEPTA transportation supervisor was killed early Saturday when his BMW car sideswiped another vehicle, struck a concrete barrier, and overturned several times while traveling south on the Roosevelt Boulevard, Pennsylvania State Police said.

Ivan Quarterman, 52, of Sicklerville, N.J., was transported to Hahnemann University Hospital, where he was pronounced dead, police said.

Quarterman was traveling at a high speed about 2:28 a.m. Saturday when he struck another car in the right lane of the Boulevard off-ramp to I-76 eastbound. The woman whose car Quarterman struck was not injured, police said.

SEPTA spokesman Andrew Busch confirmed that Quarterman was a "veteran" SEPTA employee, who was off-duty and driving his own car at the time of the accident. Police said Quarterman was driving a 2004 BMW 325.

-- Linda Loyd