Truckies want changes after another fatal truck crash on the South Eastern Freeway. Courtesy: Network Ten

SPEED limits on the South Eastern Freeway will be slashed for all trucks in the wake of the horror crash which left two people dead and two others fighting for their lives.

From September 1, the maximum speed limit for light vehicles (cars) between the Stirling interchange and the lower arrester bed will be reduced from 100km/h to 90km/h. The electronic speed signs will display these changes.

For all trucks and buses, the maximum speed limit from the Crafers Interchange until the bottom of the freeway will be 60km/h and all trucks and buses will be required to move into the left hand lane.

Police Minister Tony Piccolo made the announcement this afternoon alongside Deputy Police Commissioner Grant Stevens.

“This week I’ve had discussion with both SAPOL and officers from the Department of Planning Transport and Infrastructure in regards to how we can make our roads safer and in particular the South Eastern Freeway,” Mr Piccolo said.

“In light of those discussions I’m announcing today that, from September, we are introducing two new measures to improve road safety along that stretch of road.

“The first measure is to extend to the current conditions of 60km/h which apply to trucks with five axles or more to any truck which has a gross mass of more than 4.5 tonnes.

“Additionally we are going to extend the 90km/h speed restrictions to east of Crafers — from 100 km/h down to 90 km/h.

“We are doing so to provide a safer, calmer traffic environment and as a result reduce the risk of any fatal accidents on that stretch of road.”

Police said they will be conducting an operation to ensure motorists follow the new restrictions from next month.

Mr Piccolo’s announcement came just hours after an inquest heard the truck that killed two people in Monday’s horror freeway crash was travelling at more than 150km/h seconds before ploughing into three cars.

Deputy State Coroner Anthony Schapel on Friday began his inquest into the deaths of Thomas Spiess, 56, and Jacqueline Byrne, 41.

Mr Spiess and Ms Byrne died as a result of injuries they sustained in Monday’s horrific road crash at the base of the South Eastern Freeway.

The truck’s driver, 29, and a Hahndorf woman, 49, who was in a third car, remain in a critical condition in Royal Adelaide Hospital.

SA Police experts told Mr Schapel that the Transpacific truck, believed to be fully laden with 8000 litres of sewerage, increased in velocity from 77km/h to 151.9km/h as it travelled “out of control, lurching to the left” down the freeway.

Brevet Sergeant Peter Light, from the Major Crash investigation section, said CCTV footage of the minutes leading up to the crash showed the truck travelling the final 190 metres of the freeway before the Cross Rd intersection in just 4.5 seconds.

“As the truck comes into view (on the footage) and negotiates the bend, it appears it’s out of control, that the truck lurches to the left,” he said.

“It appears to move from side to side.”

Sgt Light told the coroner it was still being investigated whether the driver had lost control of the truck.

It is understood the driver had only been in the job for a week prior to the crash.

The incident prompted trucking company Transpacific to ground its national fleet of 2800 trucks — which halted rubbish collection in some areas of Adelaide — over safety concerns.

Yesterday Mr Spiess’ wife, Jan, expressed gratitude for emergency services staff who had helped her family during their ordeal and asked for privacy while they grieved.

The inquest is the second time Mr Schapel has investigated a death on the SE Freeway.

Six months ago, he handed down preliminary findings into the October 2010 death of John Posnakidis, 42, who was hit by a truck as he waited at a bus stop.

At that time, Mr Schapel said there was “an air of inevitability” that another driver would not use the freeway’s arrester beds and “there will be a repeat” of the incident “or worse”.

Brevet Sergeant Light said discussions with the driver’s co-worker had revealed the trucks were not originally intended to travel into the city that day.

Instead, the co-workers were to drive two trucks — one carrying 12,000L of sewerage, the other 8000L — to a depot at Heathfield.

They headed toward the city instead after discovering that the Heathfield depot was closed.

Brevet Sergeant Light tendered two DVDs of CCTV footage to the court, comprising vision from five cameras along the length of the freeway’s down-track.

The Advertiser applied for access to reproduce the footage, however Mr Schapel said he would not be releasing the images at this point in the inquest.

The first video clip shows the truck leaving the Heysen Tunnels at an estimated speed of 75.3km/h, well below the posted speed limit of 100km/h.

In the second clip, its speed has increased to 77km/h.

Brevet Sergeant Light said the third clip depicted the truck approaching the “last chance” arrester bed — at which time “you see the brake lights illuminate” briefly.

He said the truck’s estimated speed at that time was 93km/h.

In clip four the truck travels the distance between the arrester bed and the bus stop at which Mr Posnakidis died but, in the fifth clip, the nature of its driving changes.

“As the truck comes into view (on the footage) and negotiates the bend, it appears it’s out of control, that the truck lurches to the left,” Brevet Sergeant Light said.

“It appears to move from side to side.”

He said that point was 630m from the Urrbrae intersection and the truck’s estimated speed, at that moment, was 109.4km/h — the speed limit for that section was 60km/h.

The final clip shows the truck move past the toll gate and into the down-track’s left-hand slip lane, where it collides with a white car before travelling into the intersection.

“The distance from the toll gate to the (point of) impact was 350m,” Brevet Sergeant Light said.

“The truck travelled that distance in 8.5 seconds ... its estimated average speed was 148.2km/h.

“It travelled the final 190m (to the point of impact) in 4.5 seconds with an estimated speed of 151.9km/h.”

He said the white car was propelled “in a straight line” across the intersection and struck the decorative wall sculpture on the Glen Osmond Rd.

The truck continued on and collided with the passenger side of Mr Spiess’ car, which had crossed the intersection from Portrush Rd and continued along Cross Rd.

That impact caused the truck to rotate clockwise and it then “sandwiched” Ms Byrne’s car, which was waiting at the Cross Rd traffic lights.

Having heard the evidence, and knowing further investigation was to come, Mr Schapel made a preliminary recommendation.

“This court has power to make recommendations ... in an appropriate case, that power might be exercised sooner rather than later,” he said.

“If the evidence suggests (ways) to prevent a repeat of an incident, should (recommendations) be implemented that can be achieved simply or expeditiously, it would perhaps be idle for the court to sit on that knowledge.”

Mr Schapel recommended all trucks, regardless of size or number of axles, be limited to travelling at 60km/h on the freeway’s downhill track below Crafers.

He called for the low gearing section of the freeway to be extended from Crafers to the Urrbrae intersection where the crash occurred.

Mr Schapel said the State Government should make a public announcement that drivers were legally obligated to traverse that section in a low gear.

He said that, under the Australian Road Rules, that gear had to be low enough that the driver was not required to use his or her vehicle’s primary brake to slow down.

“It’s not a good idea or an optional extra to be adhered to in a perfect world — reliance on the primary brake is an offence,” he said.

“Everybody knows, or at least should know, that riding the brakes down the freeway is an intrinsically dangerous practice.”

Mr Schapel adjourned the inquest to a later date.

Mr Spiess’ wife, Jan, attended the hearing but declined to comment outside court.