looks like this old con is being used again. we had it decades ago. they wanted cheaper metal so they skipped the tumbling process which gets rid of the sharp edges. tire guys where doing a roaring trade. but council was sneaky, for reimbursement for the damage you had to take the tire to the council office which made the cost so high and the reimbursement was less than what a tire cost, people didn't bother.
also had contractors use massive sized rocks. so big cars would get stuck. one poor person had their stuck car dragged through the road works by the contractors truck and it tore up the underneath of the car.
Rural Kaipara residents affected by road-metal damage want council reimbursement