Those airbags will save your life

By Joshua Kato    
In the early hours of Saturday night, a week ago, veteran politician Jaberi Bidandi Ssali drove from Kampala, to his Bukoto home. In the car, a Toyota Premio was Saddam Gayiira, a politician with Bidandi`s political party, the People`s Progress Party (PPP). As they drove around the Kisaasi-Ntinda by pass round about, Bidandi lost control of the vehicle and rammed into a truck, coming from the other side

According to Gayiira, it was a big crash, since most of the front of the car was wrecked. “If the car did not have airbags, then we might have been badly injured,” Gayiira said. Indeed, when rescuers came to rescue the two, they saw the airbags that protected them. “It is not so common to see airbags in accident cars in Uganda,” one of the rescuers commented. He was right.

Protecting key areas.
The use of an airbag can protect your head, neck and chest areas. Airbags are fixed in by the vehicle manufacturers for safety of the driver and passengers. Normally, they emerge out of the steering wheel or from the dashboard, within a few milliseconds of the collision. “I had the collision and instantly, we were covered by the bags,” Saddam Gayiira said. Because he was the passenger, he faced the passenger seat bag, that emerged from the dashboard. 

When your head hits the airbag, the airbag starts deflating slowly, allowing you to get out of the car. In some cars, when the speed exceeds 200-300 mph, airbags deploy automatically, even in the absence of a collision, however very few cars on Ugandan roads can exceed that speed.

Most cars have them.
In Uganda, according to a survey carried out randomly amongst car owners, a big number of them do not even know if their cars have got airbags. And for those who know that the cars have them, very few of them are sure whether the bags work.  “I see the inscription airbags on the dashboard, but I am not sure if they are okay,” Boaz Butta, a driver says.

Airbags are one of the safety features that can be incorporated in your car to protect you in the event of an accident. They are known by many technical names; such as Supplementary Restraint System (SRS), Air Cushion Restraint System (ACRS), and Supplemental Inflatable Restraint (SIR). In a car that has them, they are marked with the inscription ‘SRS-air-bags’, ‘ACRS-Airbags’, etc.

They are installed in the dashboard or in the steering wheel will only be deployed, if there is a front-end collision, such as in the case of a head-on collision or within 30 degrees from any side from the core of the car. The same rule applies to airbags installed at the sides of the car. The airbag is deployed when the car is hit at a certain angle. The ones on the left won't deploy, if the collision is on the right side and vice versa.

In most vehicles on the Ugandan road, the airbags are found in the steering wheel and the passenger dashboard area. This is common in most of the fairly cheap vehicles-including Premios, Town ace Noahs, Ipsums, Spacios, Mark IIs.  The other passengers in the car do not have this facility. However in more expensive vehicles, like the Mercedes, Jeeps, Navaras etc, there are bags even on the sides and for the passenger compartments.

However, not every car has got this life saving accessory. For example, most Toyota 100 (Kikumi), Toyota Corsas do not have airbags. Passenger service vehicles especially the Toyota Hiece do not have airbags, apart from the latest models that has a provision for the steering and the front passenger.

Fasten your seat belt.
Often airbags may prove inadequate, if you aren't wearing a seat-belt. Due to the increasing number of accidents, governments in many countries have made the use of seat-belts mandatory, which is said to have effectively reduced the number of injuries due to vehicle accidents.

“Seat belts save lives of both drivers and passengers and that is why we are charging even passengers found without seat belts,” Police traffic chief Lawrence Niwabiine says. 

According to a traffic clause passed recently, a passenger found without a seat belt is fined sh20,000 on the spot. However, the latest designs in airbags can protect the person, even if he's not wearing a seat-belt. But these are models that cannot be afforded by the common Ugandan.

How it works.

According to automobile mechanic Ali Munyegera, of Ali auto works,  an airbag works on a sensor. When the crash sensor in the car detects a collision, it sends a signal to the control module which deploys the airbag. There are various types of crash sensors, like the older ones which were placed in the front of the car (in the crash zone area), and the latest micro-machined accelerometers that are installed inside the control module or the airbag brain.

Munyegera says that the micro-machined accelerometers measure the speed and severity of the collision. There are also sensors placed in doors, for deploying side airbags. The front and the side sensors only work with the front and side airbags, respectively.

The control module or the airbag brain is a small computer that receives data of the crash from different sensors, and then decides which airbag is to be deployed. It is unable to deploy an airbag, if it receives only one pulse. It would need two or more pulses from the sensors to do so. The second pulse comes from the arming sensor that is located inside the car, which senses a sudden decrease in speed.

When the control module is certain about a severe crash, it signals the squib inflater, also known as the igniter, which is an electrical device that has a thin bridge wire. As the current flows through the wire, it overheats, and ignites the airbag propellant which is made of sodium azide. Sodium azide is a fast-burning fuel that produces large amounts of nitrogen gas, which goes through filters and fills the nylon airbags.

After your head hits the nitrogen-filled bag, the bag deflates by releasing the gas through tiny holes. The cloud of smoke that fills the vehicle is actually talcum powder or cornstarch. The powder prevents the bag from sticking to itself, while it's folded inside. The nitrogen gas that is released from the tiny holes is absolutely harmless (nitrogen actually constitutes 78% of the air that we inhale). One just needs to open the doors or windows for the gas and powder to escape.

The side airbag system differs from the one in the front. It uses a stored-gas inflater which consists of a cylinder that incorporates 3000-4000 psi of compressed argon gas. The control module signals the igniter, which melts a tiny bladder inside the cylinder. The argon gas then fills the airbag and helps inflate it. Like nitrogen, argon is also harmless.

How do I know it works?
For a car that was once involved in an accident and the bags deployed, the covers of the airbags will be obviously broken/torn.  This is because the bag is used only once and it is never repaired, but has to be replaced. “The moment you see the dashboard and steering wheel cover for the airbags broken or torn, then you know they do not work,” Munyegera says.  Under such circumstances, the vehicle might have been involved in an accident and the bags were not replaced.

Munyegera says that the other way of finding out if the airbags work is when starting the car. “A symbol with the initials SRS will show on the dashboard and then moments later, it will go off and if the bags have a problem, the symbol will not go off,” he says. 

According to vehicle manufacturers directions, most airbags have got a life span of 15 years. However, in Uganda, most vehicles are over 15 years old.

“As you can see, most of the vehicles on the streets are 1990-1998 models, this means that most of the airbags may have passed their usefulness,” Munyegera says. Apparently, there are no ‘small garages’ in Uganda that can replace airbags. You either take your vehicle to big car workshops, but even then, the cost of re-installing an airbag in an over 15 year old vehicle may be the same as buying another car. Quite prohibitive.