Caldwell County and Department of Public Safety investigators are trying to determine the cause of a head-on collision that killed two drivers Thursday morning on U.S. 183 about three miles north of Lockhart.

Investigators did not have identification information for the victims, a man and a woman who were alone in their respective vehicles, DPS spokesman Tom Vinger said.

An Acura SUV and a Nissan Pathfinder were driving toward one another at 6:13 a.m. on U.S. 183 near FM 1185, Vinger said. One of the vehicles crossed the center line. Both drivers were pronounced dead at the scene, Vinger said.