Jakarta –
The case of a truck accident suspected of brake failure with a number of fatalities has occurred again in Indonesia. Last year there were big events, namely in Balikpapan, East Kalimantan and Cibubur, West Java. Now the case of a truck crashing into a traffic light occurred at the exit of the Bawen Toll Road, Semarang, Central Java. What causes a truck to experience brake failure?
Semarang Police Chief AKBP Achmad Oka explained that during the examination the truck driver had also provided several statements. One of them is that the truck was on its way from Semarang to Solo.
At first, the truck’s braking condition was no problem. The driver only discovered the condition of the failed brakes after overtaking the bus shortly before it finally hit dozens of vehicles that were stopped at the traffic light.
“As we approached the crime scene, that is the result of our examination, he tried to overtake a bus, then suddenly the brakes failed,” he said.
Even so, Oka stated that he would still wait for the results of the crime scene investigation to determine the cause of the accident. Currently, the bus driver and attendant are still being questioned by the police.
“However, this is information from the driver. Later we will see what the crime scene results are like, we will see whether they match,” he said.
In this incident, the unladen truck drove out of control and hit dozens of vehicles that were stopped at the traffic light at the Bawen Toll Road exit intersection on Saturday (23/9/2023).
Causes of truck brake failure
Trucks can experience brake failure due to incorrect habits when using brake devices. Drivers only rely on conventional brakes (service brakes), which makes the brake pads hot and less biting. So that the air pressure in the brake system is reduced
Continuous or excessive use of service brakes can cause the brake lining to overheat which results in the brake lining friction coefficient decreasing along with the increase in lining and drum temperature (brake fading).
Truck drivers should be able to combine various braking systems to reduce the speed of their vehicle. Apart from the service brake, it can also be combined with an engine brake or exhaust brake, aka air brake or retarder.
“The brake workload is heavy, therefore APM has prepared it by providing brakes other than service brakes or foot brakes, namely exhaust brakes or retarders, where every deceleration must use an exhaust or retarder,” explained the Instructor and Founder of Jakarta Defensive Driving. Consulting (JDDC) Jusri Pulubuhu some time ago.
The National Transportation Safety Committee (KNKT) said that almost 90% of total truck and bus accidents due to brake failure occurred on downhill roads. This is the same situation as the Balikpapan truck accident and the Pertamina Cibubur truck accident, where both also had accidents on declining road conditions.
“Cases of brake failure (on trucks and buses) usually occur due to several reasons, namely: declining road conditions, overheating of the lining because the brake pedal is forced to work optimally, and malfunctions,” said Senior Investigator of the National Transportation Safety Committee (KNKT) Ahmad Wildan, several last time.
In the KNKT report regarding a truck accident at Simpang Rapak, Balikpapan, East Kalimantan on January 21 2022, it was found that the driver was unable to anticipate brake failure due to using the brake pedal on a downhill road.
Braking on a downhill road using a service brake or pedal brake is very dangerous, because the driver will be forced to press the brakes repeatedly and this risks causing the brakes to fail. Therefore, every driver must understand this technology, that when trucks and buses go downhill, they must use the auxiliary brake to reduce the vehicle’s speed, and not use the main brake.
When the air pressure reaches 5 bar, the driver has difficulty pressing the brake pedal because it feels hard so the driver cannot brake again. Furthermore, when faced with a malfunctioning brake system, the driver tries to shift to a low gear.
That is why the KNKT prohibits the use of additional horns that take a source of compressed air from the same air tube used for braking and clutching, because this will accelerate the drop in air pressure in the wind tube.
“This is very unlikely to happen because at that time the downward thrust force was very large, and the condition of the existing gear in the maximum working position restrained the wheel rotation. When the driver shifts to low gear, it will automatically go into neutral first before going into gear “low, and this actually increases the wheel rotation even higher, so that the synchromesh is unable to respond and in the end the gear remains in the neutral position,” said the KNKT report.
When the gear is in the neutral position, the earth’s gravitational pushing force is maximum because there is nothing holding it back, so the truck’s speed when it crashes is at high speed. This speed is not the speed of the engine or carried out by the driver, but rather the speed due to kinetic energy which is triggered by very large potential energy.
In some cases, the driver makes a final effort by pulling the hand brake, but this is in vain because in both the full hydraulic brake and combination brake systems, the hand brake only functions as a parking brake, and will not be able to hold the vehicle in a downhill or uphill position, let alone is at high speed.
Wildan explained that in the investigation carried out by the KNKT regarding brake failure, this problem was discovered several times. Another factor that also causes the brakes to fail is the driver’s error in using gear when traveling on downhill roads.
“Failure to brake on downhill roads is often triggered by incorrect driving procedures where they use high gear and brake using the foot brake without taking advantage of deceleration by the engine and exhaust brake,” concluded Wildan.
Watch the video “Truck hits cars and motorbikes in Jatibarang area, one person dies”
(administration/citation)
2023-09-24 12:34:53
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