Investigation into crash that killed 2 TDOT contract workers could take months

WATCH: Investigation into crash that killed 2 TDOT contract workers could take months

SHELBY CO., Tenn. — Nearly two weeks after a tractor-trailer accident killed two TDOT contract employees and injured a state trooper, the investigation is still ongoing.

FOX13 spoke to a lawyer who broke down what questions the driver might face.

Original Story: 2 contractors killed, trooper injured in crash in Tennessee

Content Continues Below

Thomas Greer has represented victims of tractor-trailer crashes in civil court. FOX13’s Greg Coy shared an email from the state police with Greer. It outlines what direction the investigation might take.

Greer explained how that can help find out what happened and if charges will be filled.

Download the FOX13 Memphis app to receive alerts from breaking news in your neighborhood.

Trending stories:

“Not every crash is a crime," Greer said.

Currently, the driver of the 18-wheeler, Mervin Crigler, has not been charged.

In their email, the Tennessee Highway Patrol said it will test for alcohol and drugs when physically possible.

Greer said federal law requires the test and the standards for commercial truck drivers are rigid.

"Truck drivers are not allowed to have any alcohol in their system what so ever," he said.

According to the email, the THP will also examine "a vehicle's onboard computer systems." That's the so-called black box in the cab which investigators can use to verify Crigler's driving log.

"How fast was this driver going right before the wreck? Was there a hard break? How many hard breaks -  meaning was he driving recklessly - hitting his breaks fast and then speeding up?” Greer said. “It will give you all kinds of information."

The THP will also check out the truck to see if it yields any clues about what happened.

"How much damage was done to the vehicle?  There are math formulas to determine speed upon impact.  They also want to look at mechanical failure,” he said. “Were the breaks in good order?  Was there some other explanation for the wreck?"

The THP would not say how long the investigation will last, but Greer speculates it could be months before they decided if criminal charges will be filed.