WASHINGTON —  A Bush administration official says Dr. Jeffrey Runge (search) will resign as administrator of the National Highway Traffic Safety Administration to become chief medical officer at the Department of Homeland Security.

Runge plans to step down as the Bush administration's top traffic safety official in late August for the new position at Homeland Security, said a Bush administration official who spoke only on condition of anonymity because he did not want to pre-empt an announcement planned for later Thursday.

Runge, an mergency room physician from Charlotte, N.C., has led NHTSA since 2001. As chief medical officer, he would oversee bioterrorism policy and coordinate responses to any biological attacks under reforms at the 2-year-old agency.