Air bags are safety devices that were developed to supplement the protection
provided by seat belts. Transport Canada has received complaints from the
public concerning air bags that have deployed in low-speed collisions,
causing injuries, and incidents in which they have not opened when it seemed
they should have.
Each air bag is equipped with a control mechanism that senses sudden
deceleration. When activated, the sensor sends an electrical signal that
ignites a chemical propellant, and when ignited, this propellent produces
nitrogen gas, which inflates the air bag. This process occurs very quickly—in
less than one-twentieth of a second—faster than the blink of an eye. Most
air bags have internal tether straps that shape the fabric and limit how
far outward the bag moves. Vents in the rear allow the bag to deflate slowly
to cushion the head as it moves forward into the deploying air bag.
Sensors deploy air bags only when deceleration exceeds a minimum threshold.
If the change in speed due to an impact is lower than the threshold, the
air bag will not open. In low- to moderate-speed collisions, the seat belt
alone is usually sufficient to provide adequate protection to the head,
chest, and hips. However, in high-speed crashes, the seat belt may not
be able to prevent the head from striking the steering wheel. Air bags
protect the head and face as they move forward; consequently, sensors are
set to respond in frontal impacts, not in rear-end collisions, side impacts,
or rollovers. Only the seat belt is effective in these latter types of
crashes. Air bags may deploy in undercarriage impacts and angled collisions,
including side impacts, where there is sufficient longitudinal deceleration.
What appears to be smoke may be present in the vehicle following the
deployment of an air bag. This is caused by the powder used to prevent
the folds of the air bag from sticking together and by residual combustion
products.
#2 Why Do Air Bags Sometimes Cause Injuries?
Air bags provide good protection to the head and face in serious crashes;
however, because they open so quickly, they can cause injuries. While most
of these injuries are minor, consisting only of bruises and abrasions,
some are more serious, such as broken arms. Small people, who tend to sit
closer to the steering wheel, are more likely to be hurt by a deploying
air bag than those who are taller and sit further away. Children are
particularly vulnerable. Improperly restrained children, unrestrained children
sitting or standing close to the dashboard, and infants in rear-facing
restraint systems installed in the right-front seat are at high risk of
injury.
In low-speed collisions, air bags are not necessary in order to prevent
injury. However, the deployment threshold of many current air bag systems
is quite low—equivalent to a vehicle striking a concrete barrier at 15
to 25 km/h. As a result, some motor vehicle occupants are sustaining
injuries that could have been avoided had the air bag not deployed.
#3 What Can We Expect of Air Bag Systems
in the Future?
Currently, Transport Canada does not require that air bags be installed
in vehicles; however, when they are part of the occupant restraint system,
they must meet specific safety requirements. Generally speaking, our approach
is to set performance standards rather than to stipulate the installation
of particular hardware. In this instance, the Regulations specify vehicle
test conditions and injury criteria that are designed to ensure effective
levels of occupant protection in serious crashes.
Motor vehicle manufacturers are in the process of developing "smart"
air bags. Already some possess two thresholds of activation, depending
on whether or not a person is belted. If an occupant is not restrained,
the air bag deploys at a minimum deceleration threshold; however, if the
belt is in use, it deploys only at a second, higher level. Such dual-threshold
deployment systems will become the norm, allowing air bags to provide some
protection to the unrestrained, without needlessly injuring belted motorists.
Occupant-presence sensors will prevent passenger-side air bags from
deploying when there is no one to protect, thereby avoiding unnecessary
replacement costs. In addition, proximity sensors will gauge how close
an occupant is to the air bag module, and warning systems will signal occupants
when they are out of position, for example when a driver has fallen asleep
and is slumped over the steering wheel. Dual-stage inflation units, working
in conjunction with proximity sensors, will allow for less violent deployment
of the air bag if someone is too close to the module.
Currently, some vehicles are equipped with manual cut-off switches
that disable the passenger-side air bag if an infant restraint system is
installed in that seat. In the future, switches may be replaced by
automatic systems that will detect the presence of the infant restraint
and prevent the deployment of the air bag.
#4 What Can I Do in the Meantime?
Until advanced air bag technology becomes widely available, Canadians
should attempt to maximize the protection afforded by current occupant
restraint systems by taking the following precautions:
Always use your seat belt and ensure that your children
are buckled up. Make sure that the lap belt is positioned across the pelvis
and that the shoulder belt lies across the chest and over the shoulder.
Do not leave any slack in the seat belt. Move the seat as far to the rear
as possible in order to provide sufficient space for the air bag to deploy.
Do not use a rear-facing infant restraint system in
the right-front seat unless the air bag has been deactivated by a cut-off
switch.
If you have any questions about air bags, or
any other safety-related issue, please telephone the Road Safety Information
Centre at 1-800-333-0371(long distance, Canada) or 1-613-998-8616 (Ottawa
region and from other countries)
I would like to thank Transport Canada for allowing me to copy
their leaflet CL9601E - June 21, 1996. You can find more automobile tips
at Transport Canada
THEM'S THE BRAKES
You know it's time to have your brakes checked when they exhibit one
or more of the following signs:
1.When your car pulls to one side. You may have an underinflated tire,
brakes in need of repair or steering problems.
2.When you are driving and you feel the brakes stick or a loss of engine
power. Your brakes may not be releasing properly which can lead to total
brake loss.
3.When your brakes grab when lightly applied. This could be caused by
grease or oil contaminated linings or a loose or broken brake part.
4.When your brakes squeal, chatter, groan, grind, screech, bang, etc.
Please have your brakes checked immediately.
5.When your brakes need a lot of pressure to work or the pedal needs
to be near the floor before it works.
6.When your brake pedal, steering wheel or entire car vibrates when
you step on the brakes.
NHTSA 23-96 Monday, May 6, 1996 Contact: Barry McCahill
Tel. No. (202) 366-9550
NHTSA ANNOUNCES TWO CHILD SAFETY SEAT RECALLS
The National Highway Traffic Safety Administration today announced child
safety seat recalls being conducted by Century Products Company of Macedonia,
Ohio, and Evenflo of Piqua, Ohio.
The Century recall involves 11,000 Century SmartMove Model 4750 convertible
child safety seats manufactured between Nov. 27, 1995 and Feb. 13, 1996.
They are being recalled because a mismatch of latching components could
allow the buckle to release during a crash.
NHTSA Administrator Ricardo Martinez, M.D., told parents who had no
suitable alternative to safety seats affected by this recall to continue
using them until they receive and install the retrofit kit from the manufacturer.
An unrestrained child is at a much greater risk of injury in a crash
than a child in a restraint system, he explained.
To obtain a free retrofit kit, owners of these seats should call Century
at (800) 583-4093 or write to Century Products Company, 9600 Valley View
Road, Macedonia, Ohio 44056.
The Evenflo recall involves 10,423 Evenflo Trooper Adjustable Shield
child safety seats, Models 219140, 219164, 219180, 219186 and 219188 built
between Nov. 27, 1995 and Jan. 22, 1996. Evenflo is replacing the instruction
pamphlet accompanying these seats because it switched the instructions
for toddler and infant use. This error could lead some owners to believe
that infants smaller than 20 pounds can ride facing forward. Evenflo will
provide owners with a new, corrected instruction pamphlet.
Owners of these Evenflo child safety seats who wish to contact the company
for a new instruction pamphlet should call (800) 837-4002 or write to Evenflo
at 1801 Commerce Drive, Piqua, Ohio 45356.
If you want to check to see if the child safety seat that you are
using has been recalled click here. NHTSA
Child Safety Seat Recalls
