A fatal crash involving a TTC bus and a flatbed truck is now the subject of a $4.25-million lawsuit.

Jadranka Petrova, 43, died on Aug. 30, 2011, when the TTC bus she was riding on hit a flatbed truck on Lawrence Avenue East.

A police investigation led to charges against the bus driver, which included criminal negligence causing death and marijuana possession.

Petrova’s surviving family announced Tuesday that it had launched a lawsuit, naming the TTC, the bus driver, William Ainsworth, as well as the flatbed truck driver and a trucking company, as defendants.

The lawsuit claims that the bus driver was “incompetent” because he had allegedly been smoking marijuana, and that the TTC was negligent for allowing him to allegedly drive while under the influence.

Furthermore, the lawsuit alleges that the trucking company failed to keep its equipment in proper condition and permitted an “incompetent” driver to operate the flatbed truck, who subsequently slowed down on the road without warning.

None of the lawsuit claims have been proven in court.

In a statement, lawyer John McLeish said Petrova’s husband and children are “devastated by the senseless loss of their wife and mother, who was the heart and soul of their family.”

McLeish said his law firm “is standing up on behalf of her family in hopes that other families can avoid the same anguish."