THE BRAKE testing system commonly used for annual vehicle safety inspections in Australia and New Zealand is not safe for road users, because it routinely gives a pass mark to weak and faulty braking systems.
This was the finding of a recent Adelaide University study, which showed a car with both rear brakes disabled could easily pass the common decelerometer brake test.
That’s despite the fact its stopping distance was increased by 30 percent or 8.1 metres compared with a correctly functioning braking system.
(The test didn’t even detect that the rear brakes weren’t working!)
A further test with the front brakes limited to 66 percent of maximum brake pressure increased stopping distance by 45.8 percent or 12.3 metres.
Surely the car didn’t pass this brake test? It certainly did.
These tests were conducted as part of an in-depth study by the University of Adelaide Centre for Automotive Safety Research, with the support of the Commonwealth Government.
The study measured the ability of four brake testing methods to detect mechanical or hydraulic brake faults.
It compared the most common type of test – a decelerometer brake test – as well as a roller tester, a plate brake tester, and the stopping distance test.
A Safe T Stop plate brake tester was used, as the only Australian designed and manufactured plate brake testing system.
Pass and fail marks were based on the minimum brake performance criteria from the NSW Authorised Inspection Scheme, which are similar to those in other states and territories, and in New Zealand.
Only the Safe T Stop plate brake testing system detected all the brake problems and correctly issued a ‘fail’ result every time.
One extreme test saw front brakes limited to 54 percent of maximum brake pressure, which increase stopping distance from 80km/h by 73.5 percent – that’s 19.8 metres, or more than four car lengths!
You guessed it! Another pass with flying colours based on a decelerometer test.
It was only with the rear brakes disabled AND the front brakes limited to 66 percent of maximum brake pressure that the decelerometer finally offered a ‘fail’ result…
This independent study is the first of its kind globally in more than 30 years.
Yes, that’s right. There hasn’t been academic research into the effectiveness of brake tests since before we had ABS; we’re still using the same technology to test brakes as before we had traction control, GPS or mobile phones.
The decelerometer brake test gave a pass mark to weak and faulty brake systems that replicated common conditions, including seized calipers, blocked hoses, faulty proportioning valves, air in the system and master cylinder problems.
And all but one type of test failed to detect faults that were present.
And the conclusions?
According to the University of Adelaide Centre for Automotive Safety Research, “the (Safe T Stop) plate brake tester was considered to offer the most comprehensive report on a vehicle’s brakes and identified brake faults that reduced stopping power and caused left to right imbalance on either axle.
“By measuring the front to rear brake force balance, the plate brake tester identified when the rear brakes were severely compromised, but the vehicle still provided a relatively high overall deceleration,” the study concluded.