Sippy Downs ramp report released

A Main Roads report has indicated surface contamination, such as oil, was the most likely road factor contributing to a fatal crash at a Sunshine Coast off-ramp in May, Transport and Main Roads Minister Paul Lucas said today.

Mr Lucas today released a departmental investigation into road conditions at the south-bound ramp from the Bruce Highway to the Sunshine Motorway at Tanawha on 21 May, the day of the crash.

“Tragically, a driver died after her vehicle left the road and went into a culvert,” Mr Lucas said.

“A second vehicle also left the road and struck the first driver's vehicle which was in turn forced into its driver, who tragically received fatal injuries.

“The report I have received today investigated road conditions only – other factors, such as vehicle or driver-related factors – will be covered in a separate police investigation into the crash, which is now being completed.”

Mr Lucas said the report into road conditions made the following findings:

• That an estimated 11.2 million vehicles have used the ramp between October 1995 and June this year, for a total of seven reported crashes.
• That the level of crashes on the ramp would not have triggered detailed investigations under Main Roads' crash investigation criteria, which were tightened following a series of crashes on the Bruce Highway at Federal in 2005.
• That road pollution such as oil or diesel was reported to police by an eye-witness as being on the road at the time of the crash
• That such road pollution, in combination with light rain after a period of dry, can significantly reduce available friction.

“I am advised an eye-witness told police that, at the time of the accident on 21 May, they saw a 'rainbow-coloured' film on the road at the point that the second vehicle lost control. The report found such a film indicates the presence of oil or some other contaminant,” Mr Lucas said.

“I am also advised it is likely that this surface contamination, combined with light rain, significantly exaggerated the road-surface conditions at the time.

“But I must stress, until police investigations are complete – and possibly not even then – we will not know the ultimate cause of this crash.”

Main Roads Chief Engineer, Ian Reeves, said the report also found the design of the ramp was satisfactory for the requirements placed upon it – the ramp joins two motorways and includes a further diverge to give access to a local road.

“The ramp configuration does require drivers to pay attention and, in some circumstances, to corner and brake heavily,” Mr Reeves said.

“The crash history shows the majority of motorists have been able to do this in all weather conditions without incident.

“Speed monitoring carried out as part of the investigation confirms this, showing more than 7000 vehicles – some 15% of the 50,644 motorists who used the ramp over a two-week period – were travelling at more than 80km/h in all weather conditions, with no further reported crashes.”

Mr Reeves said the investigation showed an increase in vehicle numbers on the ramp – a doubling of traffic between 2000 and 2007 – combined with the extra cornering and braking at the ramp curve, had led to the aggregate in the roadway ‘polishing’ more quickly than otherwise could reasonably have been expected.

"Polishing is normal on all stone surfaces, and relates to the wearing away of the stone by traffic," Mr Reeves said.

"It has nothing to do with the type of surface that has been laid. The polishing takes place at different rates on this ramp - in some places it's better than others.

"At the worst point of polishing it is marginal in wet-weather conditions.

“However, it should be noted approximately 1.4 million vehicles a year travel over this road and around 225,000 of them are over the 80km/h advisory and/or regulatory speed limit – without a significant crash history.

"In order to significantly improve skid-resistance on the ramp, Main Roads will place a high-friction cover treatment, called calcined bauxite, over the top of the existing surface.

"This cover treatment is not often used, as it is expensive and has to be laid by hand. It is also difficult to apply. Main Roads will be speaking to other roads authorities around Australia, and will find the best in the business to carry out this covering treatment.

"Once in place, this will significantly improve skid resistance on this ramp."

Mr Lucas said the report made a number of other recommendations, relating specifically to the ramp and to other location more generally.

"Based on its findings, the report makes five recommendations specifically relating to this ramp, and six more general recommendations, including one relating to ramps in similar situations," Mr Lucas said.

"The site-specific recommendations include actions to improve signage and visibility, as well as the high-friction treatment. In the course of this investigation, Main Roads lowered the ramp speed to 70 km/h from 80km/h. It is recommended that this speed reduction be made permanent.

"Main Roads will also review exit ramps from 100km/h and 110km/h motorways and highways, carrying out detailed friction testing, as part of the ongoing program to enhance the safety of the road network."

Mr Lucas said the findings of this report would now be presented to Professor Rod Troutbeck, who is carrying out an independent review into the use of Stone Mastic Asphalt on on-ramps, off-ramps and service roads.

"Once Professor Troutbeck has finished his report, Main Roads will review his recommendations and action them accordingly," Mr Lucas said.

"This crash followed a tragic set of circumstances," Mr Lucas said.

"Main Roads will now act to make sure that those things in can act upon are carried out swiftly. This will lead to a more forgiving road surface.”