No excuses for truck defects: SA govt

Trucking companies have no excuse for failing to maintain vehicles after a number of South Australian road deaths, the state's transport minister says.

Almost half of the 70 trucks inspected by police in Adelaide on Tuesday had major defects which required repair before they could be allowed back on the road.

Police launched the operation after two people were killed in August when a sewage truck travelling at high speed slammed into three stationary cars at a freeway intersection.

The accident took the number of people killed in truck crashes in SA this year to 15.

Another potentially deadly crash at the same intersection was avoided on Monday when police diverted an out-of-control truck.

Transport Minister Stephen Mullighan says there is no excuse for failing to meet safety standards.

"We've got, at the very least, a small number of operators who seem to be chancing it," he told ABC Radio on Thursday.

"They're chancing it because (either) they think they can get away with it or they think it's a risk worth taking, even if they are caught, because the penalties aren't sufficient."

The Transport Workers Union (TWU) pointed the finger at corporate clients, saying trucking companies were under pressure to cut corners to meet unrealistic deadlines.

Speaking at an Adelaide memorial on Thursday for people killed in truck crashes, TWU national secretary Tony Sheldon said drivers were being pushed to the edge.

"There is not one driver at this protest that would be surprised at the number of defects that have been found in the trucking industry in this latest test," he told reporters.

Mr Mullighan said the government would consider subsidising the cost of removing trucks from arrester beds to ensure there was no disincentive in using them.

But fixed maintenance checkpoints were unlikely to be effective, he said.

"If there are truck drivers or trucking companies who suspect that their rig isn't very well-maintained, they'll just avoid it," he said.