"The truck did not stop in time, and jack-knifed as it approached the lights," they explained.
"The rear trailer hit the stop/go lights, which appears to have then hit the traffic controller."
The traffic control worker was taken to Hawke's Bay Hospital with moderate injuries but was discharged that night with bruising.
The council spokesperson described it as an "evolving incident", and said a full incident report was being worked on by the contractor.
"This is not a common occurrence as safety standards in the roading industry are very high."
Fulton Hogan has been approached for comment about the incident, as has Sandfords Rural Carriers, a spokesperson of which said they could not comment at this stage.
It was one of three incidents emergency services were called to over the space of an hour in wet conditions around the region yesterday.
A car was hit by a train at a railway crossing on Victoria St in Waipawa, and then struck another car, at about 1pm.
Two people were treated for minor injuries and another was treated for moderate injuries by paramedics at the scene.
Another person was then seriously injured when a car crashed into a pole on Maadi Rd in Onekawa at about 2pm.
The crashes continued that evening, with police also called to an incident on Awatoto Rd at about 6.35pm where a car had gone into a ditch.
One person received moderate injuries and was taken to Hawke's Bay Hospital.
A car also crashed into a power pole near the intersection of Gordon St and SH50 in Fernhill at about 7.15pm, closing the road for some time as it brought down powerlines and caused power loss to more than 700 homes.
There were no reported injuries and all power was restored at about midnight.
