Ira Blackstock, 53, who is charged with vehicular homicide in the twins' deaths, argued through his lawyer that he needs his license to drive for work.
The agreement to let him back on the road was signed in Skagit County on Friday morning. He can now drive his blue 1999 Dodge Ram pickup only in connection with his job as a roofer.
According to the Washington State Patrol, Blackstock was driving south on Highway 20 south of Anacortes on Oct. 31, 2013, in a 2006 Ford Mustang when he crossed the center line and slammed head-on into an Acura Vigor with the two twin sisters and their friend inside.
One sister, Janeah Goheen, 17, died at the scene. The other sister, Janesah Goheen, died several days later at Harborview Medical Center in Seattle.
Their friend, Alysha Pickler, 18, was also injured in the crash.
State trooper Mark Francis said Blackstock showed signs of impairment at the scene.
Blackstock's driver's license was confiscated after the crash and he was prohibited from driving, but that restriction was lifted effective Friday. He can now drive his pickup between 7:30 a.m. and 7:30 p.m. on Whidbey Island and in Skagit County and only for his job as a roofer.
He is free on $270,000 bail while awaiting trial.