The horrific truck crash at the bottom of the South Eastern Freeway on Monday has claimed a second life.

Police said this morning that a 41-year-old woman from Ingle Farm had died overnight in the Royal Adelaide Hospital

The woman was a driver of one of three cars hit by a sewage truck which failed to negotiate the Cross Road corner early on Monday afternoon. The driver of one of the other cars, a 56-year-old man from Hallett Cove, was killed in the collision.

The truck driver, a 29-year-old man from Netley, and a 48-year-old woman from Hahndorf remain in a critical condition.

Meanwhile, the company which owns the truck involved in the crash has grounded its entire national fleet as it conducts an internal investigation.

Transpacific chief executive Robert Boucher said the company had taken the decision to ground its fleet to ensure its vehicles were roadworthy.

“This is not a decision we have taken lightly, however we believe it is the right thing to do given the serious nature of Monday’s accident,” he said in a statement.

“The driver had undergone thorough safety training prior to being cleared to drive our truck.”

Boucher said Transpacific had fully co-operated with police, providing them with access to the company’s trucks and maintenance records.

Police have said it appeared the driver of the sewage truck was travelling at considerable speed before the crash.

Transport Workers Union state secretary Ray Wyatt said tight operating margins were forcing trucking companies to delay essential maintenance and keep trucks on the road for too long.

“The causes of the crash are under investigation,” he said in a statement.

“But nationwide, we’re seeing more and more truck crashes and fatalities as a result of speeding, fatigue and poor maintenance – all caused by clients delaying essential maintenance, setting unrealistic deadlines and keeping vehicles on the road for too long.

“That pressure is killing truck drivers, and it’s killing motorists and pedestrians.”

– with AAP