Parked semi-trucks pose a danger to drivers. Now, there's a push for change.

An unexpected danger kept Mario Gonzalez from making it home after visiting a relative in Texas this summer. 

The 74-year-old retired teacher was driving on I-37, a highway south of San Antonio. Just before 10 p.m. local time, his pickup slammed into the back of a semi-truck parked on the side of the road. The truck's lights were off, and it was dark out. Gonzalez was speeding when he left the freeway, but an investigation found that he hit the brakes before the collision. 

"They literally had stopped, parked and turned off the lights in the roadway," said Bob Hilliard, an attorney representing Gonzalez's family in a lawsuit against the trucking company. The company is denying any wrongdoing.