The issue of truck safety has been a hot topic lately with the governments new Road Safety Remuneration System coming into effect this month. The aim of the initiative by government is to reduce the number of truck crashes caused by drivers rushing and ignoring road safety in order to make more money. One such incident occurred on Thursday on the Pacific Highway when a truck crash caused significant delays to motorists, spilling its load across the highway.
Abc.net,au reported on the accident in its news blog:
Motorists are being warned there are significant delays on the Pacific Highway north of Newcastle after a truck crash earlier today.
A B-double truck rolled on the highway near Bulahdelah just before 3:00am (AEST), blocking both north and southbound lanes.
The truck spilled its load of frozen goods as well as a large volume of diesel, which has damaged the road surface.
Traffic began moving again just before 6:00am (AEST) but at one stage was banked up for several kilometres either side of the crash site.
The Traffic Management Centre says the truck salvage operation and diesel clean up was complex and continued for most of the day.
A TMC spokeswoman says while all lanes were open by 5:00pm (AEST), southbound traffic is queued for 15 kilometres and motorists should expect a 1.5-hour delay.
She says northbound lanes are backed up for eight kilometres, causing a 45-minute delay.
Source: https://www.abc.net.au/news/2012-07-05/highway-delays-after-truck-crash/4111884
But what exactly occurs during a truck roll over? Often when the trailer has a higher centre of gravity than the truck it can cause a roll over. That is why truck loading specifications are so important.
According to BP, it all has to do with physics, this is what they had to say on their website:
What Happens in a Roll Over?
The fifth wheel and tractor suspension will also absorb some twisting, but at some point the inside drive tyres lift off the ground. The driver is insulated from the rollover up to this point. His first indication of a problem is visual: he sees the trailer rolling over in his mirror before he feels the tractor rolling.
Often the driver will insist that the load has shifted and rolled him over. From his perspective, this is what seems to happen. The load will shift during the roll over, but as a result of the roll over, not the cause.
Contributing Causes
The arc of the curve and the bank of the roadway ?
- Steepness of the crown of the road
- Liquid sloshing: worst case. liquid sloshing occurs when tankers are filled to 40-70% capacity, and the tanker is not equipped with baffles.
- Speed at which you enter the curve or ramp
- You need friction to turn: pavement friction generated by trucks is less than that generated by a passenger car, but the effective friction demand for trucks is higher.
- High crosswinds
- Tight radius turns
- Short deceleration lanes preceding tight radius exits
- Curbs on the outside of curves
- Downgrades leading into ramps
- Unrealistic speed limits for ramps off of high speed highways
- Curves with a negative bank (usually for drainage purposes)
- Driver fatigue
- Driver inexperience in transporting loads with a high centre of gravity
- Drifting off the road, then quickly counter-steering
- Failure to anticipate sharp ramp or curve
- Entering a turn or ramp too fast
- Driver distraction
- Oversteering :
