The company pleaded guilty in the Adelaide Magistrates Court to two charges of breaching health and safety laws in relation to the 2012 incident, which federal regulator Comcare said occurred when workers were installing a 4m concrete drain pipe and a 40kg section broke off and fell into evening peak-hour traffic.

No one was hurt, even though the pipe hit two cars parked at lights on South Road in Angle Park, crashing through the windscreen of one of the vehicles.

In sentencing today, Magistrate Paul Foley found John Holland had not carried out a risk assessment for the job or ensured the work was done safely.

“The very nature of what was being done gives rise to an identifiable risk of serious harm or worse to anyone below where the work was being undertaken,” he said in his judgement.

Comcare welcomed the penalty, with CEO Jennifer Taylor saying the case was “a clear example of failing to meet work health and safety obligations”.

The case is the first criminal prosecution brought by Comcare under the Commonwealth Work Health and Safety Act, which replaced the Occupational Health and Safety Act in 2012.

A parliamentary committee is currently investigating construction practices on the South Road Superway after InDaily revealed concerns by steel fixers and other workers that “shortcuts” had been taken which compromised the structure’s safety.

These included claims that shear ties, designed to prevent the construction from collapsing during an earthquake, were not installed intact, and that workers had to heat steel reinforcement used in the structure above temperatures that may have fundamentally compromised the integrity of the metal.

Constructed at a cost of $842 million, the Superway is the most expensive road infrastructure in South Australia’s history.

-with AAP