“This crash is an unfortunate and important reminder that drivers must be aware of work zones and the safety of our employees and our contractors’ employees as they do their jobs,” Stothert said in a prepared statement.

In February, the City Council voted 4-3 to spend $450,000 to hire outside contractors to help with filling potholes in the wake of a snowy winter that produced a bumper crop of potholes on city streets.

Local 251, which is the city’s largest civilian union, has raised concerns with reporters in recent days about some pothole-patching contractors who they said are not following city safety standards.

In Wednesday’s crash, however, investigators have not yet determined whether any safety standards were violated.

The city’s contract with private pothole crews requires the contractors to be responsible for their own traffic control and the safety of their crews, said Tim Young, the city’s human resources director.