How lorry chassis could be causing fatal accidents
Fatal bus accidents are not unusual in Uganda. But the period from Sept. 18 to Oct. 14 might go down as the worst 30 days on record. In a space of a few days, four bus accidents occurred in the same region of western Uganda, killing 20 people and injuring over 100, some severely.
But even the earlier months were not safe either. In June, 28 people died and 65 were injured when two Ugandan-registered buses collided head-on in South Sudan. Earlier in May, over 60 passengers were injured when a bus accident took place in the same area.
Since 2009, bus coaches have registered the highest increase in accidents. In 2010, about 505 buses were involved in accidents compared to 456 in 2009. That is a very high number considering that in 2009, there were about 1465 buses and 1602 in 2010.
Despite the numerous bus accidents, The Independent's investigations show that the issue has not been tackled by either the police or the Uganda Bureau of Standards and the Transport Regulation Department of the ministry of Works and Transport. These departments are charged with either setting standards to avoid accidents or investigating causes of accidents. Unfortunately, they rely mainly on the traffic police who issue blanket explanations of causes of accidents like speeding, reckless driving, vehicle in poor mechanical condition, driver fatigue, and driving under the influence of alcohol.
One area that requires expert investigation is the allegation that most bus accidents occur because drivers 'lose control' of these iron-boxes on rubber wheels. If true, the question is why do the drivers 'lose control'?
Buses on lorry chassis
According to engineers familiar with buses, two claims require urgent investigations; one involves the bus's breaking system and the other is the bus body fabrication.
Historically, buses and trucks shared the same chassis but in later years specific bus chassis have been developed. As part of the changes around the 1990s, bus manufacturing underwent a push toward low-floor designs, and chassis' built specifically for buses to improve movement. In the same way although until the 1980s, many minibuses were built by applying bus bodies to van chassis, many of these have been replaced by purpose built designs. It has stayed the same only in smaller minibuses. Some of the smaller designs achieved safer mobility by moving the door behind the front wheels and on the larger buses it was achieved with various independent leaf spring suspensions which absorb shock.
Unfortunately, Uganda is one of those countries that do not have a bus design standard. This has led to a proliferation of bus-body building companies in Kampala and Nairobi, that fabricate bus bodies in all shapes and sizes.
"Some of these bus body builders are not professionals," says Brian Amimo, a certified mechatronics engineer with Spear Motors in Kampala. He says the bus body builders are hired by companies because they are cheap labour and are good at metal cutting and welding.
He said as amateurs, the artisans cannot correctly calculate the weight and size of metal supposed to be used. As a result, even without accident, the buses the amateurs fabricate leave passengers complaining about narrow seats, low cabin height, lack of enough ventilation and above all weakness of the bus body work.
The most deadly designs, however, appear to be buses that continue to be fabricated on chassis of lorries.
Fred Nyanzi Kioko, a 28-year old mechanical engineer with Skenya Motors Limited, says the problem with these buses is that a truck chassis is designed differently from a bus chassis. A truck chassis bumps up and down when driven on a murram road and the reverse is true on a tarmac road so using it in bus construction is pure suicide, he says.
Kioko adds that with the kind of bumpiness on our roads, any slight mistake like hitting a hump or stone without adequate precaution can cause a fatal accident. It gets worse if the bus is overloaded. In such a situation it cannot easily negotiate corners. He says overloading makes a bus to be "as rigid as a wheel barrow".
Kioko says when a driver tries to negotiate a corner with this kind of fabricated chassis; he will need to brake unnecessarily in an attempt to control the weight of the bus because the original strength of the chassis was compromised. Unfortunately, the brakes will not be able to handle the current weight. This causes friction in the tyre hubs causing a burn up of the tyres and eventually an accident. As a result, one of the cardinal rules of Uganda bus drivers is to go slow on breaking!
To compound the problem, Jessel Okello, an engineer with Mantrac Uganda, the Ugandan dealers in Isuzu buses says local bus body builders do not buy the required tyre drums because they are costly; Shs 3 million. Normally, motor vehicle brakes work by converting kinetic energy into heat by friction. The tyre drums are designed to aid in controlling the heat on the brakes. However, body builders consider them wastage because metallic brakes can do the job even without tyre drums.
But, Okello explains, without the tyre drums, the metallic brakes heat up so badly that the drivers dread putting their foot on the brakes, They brake only when it is absolutely necessary because they do not want them to burn their feet. Unfortunately, that results in an accident. This appears to be the reason there are more bus accidents in western Uganda than elsewhere. The roads have many winding turns and the drivers have to keep their foot on the hot brakes.
In all the October bus accident cases, police reported that either the driver lost control of the bus, swerved off the road, or failed to negotiate a bend. A casual conclusion could be that all these drivers cannot be making the same mistake. There is possibly, something wrong with their machines.
Tyres off the road!
Okello says that truck chassis' are originally six to five meters long, yet Ugandan bus owners want buses of 12 meters or more. The bus owner's motivation is greed. Instead of building standard bus bodies that sit between 50 and 55 - like the Yutong buses of Pioneer Easy Bus Ltd in Kampala, they want longer buses that can sit up to 67 passengers not to mention those standing. To get the extra length, the body builders take the six or five meters chassis of a lorry and weld on another six or seven meter for the bus body. Even original buses, which have short chassis of 10 meters long, are extended in the same way.
Kioko said that bus chassis' vary according to a bus company, for Scania it is 13-12 meters long, an Isuzu chassis is 12 meters long, a Nissan diesel chassis is around 10 to 12 meters long.
He said that chassis for buses built within East Africa are specifically designed for tropical Africa conditions and their engines are smaller in capacity compared to those imported with similar seating capacity.
Okello says if the chassis, the body weight, the weight of the passengers and other loads on the bus exceed the recommended load by about 40%; if it is coupled with reckless driving or poor service and maintenance of the bus, an accident is bound to happen.
Amimo says amateur fabricators used do not have the skill to make the right chassis extension or body for the particular chassis model that are imported into the country.
He says bus bodies come in different sizes, models, and capacities. He says when extra metals are welded on for length or bigger bodies are built on small chassis, it causes the weight at the back of the bus not to be well supported by the middle tyres alone as the front tyres support the engine. In case of overload, the front tyres are slightly off the road floor. If any accident prone situation presents itself, the bus is easily tipped off balance. He says trucks like the popular Fuso, have small chassis and small leaf spring suspensions which cannot absorb the shock of the bumps as much as a bus chassis would. He says such a bus needs less weight at the back for the bus to balance well.
But Joseph Kazibwe, a 44-year old mechanical engineer, at Muniru's Garage in Kabusu disagreed. He said there is no way a Fuso chassis elongation or building a bus on it can cause an accident. To him, the only way a chassis can spark or cause an accident is when the bus is badly maintained and when 'the driver has a braking habit'.
Kazibwe explains that chassis manufacturing companies leave a lot of space and joints in the chassis' for body builders to add whatever they feel like.
"A chassis can be turned into anything you want," he says.
He says a well-maintained Fuso chassis can make a good bus.
He, however, recommends that a body builder should install a good turbo charger to increase the power of the bus because a Fuso engine is low on speed and carries four tonnes that is equivalent to 50 passengers on a bus.
The problem is that although Fuso chassis are designed to carry four tonnes, most fabricated buses are over-loaded with a standard 67 passenger seats, standing passengers, luggage and cargo.
Watch out for tilt at the back
All bus models are prone to accidents, says Kioko, but the transport licensing board needs to have incorruptible engineering experts who can tell whether a bus has been elongated or not.
He adds that lorry-turned buses should have speed governor of 50kms per hour instead of the 80kms per hour on normal buses. He also advises travellers to scrutinise the buses they board that have a tilt at the back even when they are in parking without passengers in them.
Amimo says Ugandan policy makers should not look at what cannot be fixed overnight like the roads but they can do what the Tanzanian bureau of statistics did by specifying certain models to do specific trips. The Tanzania Bureau also has standards on tyres, spare parts, and bus bodies.
He said that route charts can be easily designed to ensure the Scania buses do hilly trips like those going to Kisoro, Kanungu, Kabale and Kapchorwa and the other buses like Isuzus and Nissans do the routes they are designed for. The Scania buses, with their six to eight gears are designed for speed. On the narrow roads of Uganda, they offer a perfect trip to death.
Recommended quick interventions
Traffic police should not concentrate on taking bribes from bus drivers. They should put safety first.
Import only buses with lower speeds. Why have cars that cruise over 200kms per hour when, in most areas, regulations stipulate speeds of below 80kms per hour.
- 22,272 road traffic accidents in 2011 with 14,438 persons killed
- Deaths due to road accidents in 2011 were 2 percent higher than the year before.
- Passengers are more like to die (37.4%) than drivers (6.4) in 2011.
- The same period saw a 6% increase in the number of traffic casualties.
- 27% of road accidents occur around 7pm-10pm.
- Only 6% of road accidents occur around 12pm and 4am.
- Source Uganda Bureau of Statistics (2012)