Two female passengers -- 56-year-old Sandra Smart and 84-year-old Dorothy Britton -- were killed Friday when Houston's taxi van struck the rear end of a stalled 18-wheeler.
It happened around 5pm on the Eastex Freeway near Laura Koppe Rd.
According to police, Houston was speeding and weaving in and out of traffic when he slammed into the tanker truck.
The METRO Police Department is assisting with the accident investigation.
METRO officials said Smart and Britton were METROLift patrons. They were being transported home from dialysis treatment as part of METROLift contracted services with Yellow Cab.
"Our first thoughts are with the victims' families during this very difficult time," METRO President and CEO George Greanias said in a release Saturday. "The METROLift program is a close-knit community and we will have counselors available to assist our dispatchers and drivers as needed."
Houston suffered minor injuries in the accident and was being treated at Ben Taub General Hospital where he was listed in fair condition. His bond was set at $100,000.
Please stay with Eyewitness News and abc13.com as we continue to follow this developing story.