auto accident
Home, Auto Repair Library, Auto Parts, Accessories, Tools, Manuals & Books, Car BLOG, Links, Index

auto accident

Auto Accidents Caused by Mechanical Failures

by Larry Carley copyright

Auto accidents are one of the risks that go with driving a motor vehicle. In 2019, more than 36,000 people died in auto accidents on U.S. roads according to NHTSA data. That's a lot of carnage on the highways!

Why do auto accidents happen? The leading cause is impaired driving. Depending on the statistics you use, roughly 34% to 45% of all accidents involve alcohol and/or drugs (legal as well as illegal). The majority of these accidents involve young male drivers on the road late at night typically on a weekend or holiday. But drunk drivers can be on the road anytime and any place, and they may hit anything or anyone who happens to get in their way. Wrong Way drivers are often drunk drivers.

"Driver error" is blamed for anywhere from 25 to 33% of all crashes, which includes such things as dumb driving blunders, failure to avoid another vehicle or object, failure to take the appropriate evasive action, inexperienced driving, driver fatigue, falling asleep behind the wheel, aggressive driving, reckless driving and distracted driving (talking on a cell phone while driving, eating, fiddling with the radio, heater or A/C controls, reading, day dreaming, etc.).

When you combine the auto accidents caused by driver error with impaired driving, human factors can be blamed for at least three out of every four accidents. The "nut" behind the wheel is almost always to blame when an auto accident occurs. So if you have been injured in an accident, you should find a good personal injury attorney to ensure you receive the compensation you deserve and the legal assistance you need to win your case.

Weather is another contributing factor that plays a role in12% to 20% of all auto accidents. This includes rain, snow, sleet, ice, fog, strong winds and smoke. Weather doesn't necessarily cause accidents. But it certainly increases the risk of having an accident by reducing traction and visibility.

If drivers fail to adjust to the changing weather conditions, it increases their risk of skidding, hydroplaning, losing control or not seeing another vehicle or obstacle.

If the road is getting slick, slow down and allow more distance between your vehicle and the one ahead of you. And if the road is getting really slick (like 100% ice covered), get off the road and find a place to stay until weather conditions improve. Better to arrive late than not at all.

Heavy rain, sleet and snow can also limit visibility, even if you have good wipers and they are running at high speed. Following the taillights ahead of you when driving under poor visibility conditions is NOT a good idea. Why? Because if the driver ahead of you runs off the road, you'll follow him


Mechanical failures are a factor in 12% to 13% of all auto accidents, according to all of the statistics I could find on the subject. In most cases, the mechanical failures can be attributed to normal wear or a lack of proper vehicle maintenance, not poor design or manufacturing defects (though there have been plenty of examples of the latter over the years).

If you have been involved in a car accident which you suspect was caused by a manufacturing defect, the first thing you should do is consult a good personal injury attorney. They will review your case and help you recover costs and damages that resulted from your accident.

Although mechanical failures are involved in only a small percentage of all auto accidents, they still represent a risk factor. So why take unnecessary chances? The risk of having an auto accident due to mechanical failure can be greatly reduced by taking better care of your car:

* Check the inflation pressure in all of your tires regularly (at least once a week, or when you get gas, and always before a long trip). Inflate tires to the recommended pressure in your owner's manual or the tire inflation guide decal in the glove box or door pillar.

* Check your tires for unusual or uneven wear, and replace the tires if they are worn down to the wear bars on the tread. Tires more that are more than six years old should also be replaced. See Watch Out for Old Tires.

* If your brakes are making noise, if the brake pedal is low or sinks to the floor, if the pedal pulsates or feels soft or spongy when you apply the brakes, or the brakes pull to one side, your vehicle has a brake problem that needs to be diagnosed and repaired. Don't drive with bad brakes.

WARNING: If the red BRAKE warning light comes on when you apply the brakes, your car may have a serious brake problem that requires immediate attention. Your vehicle may be unsafe to drive.

If the amber ABS warning light comes when you apply the brakes, or if the ABS warning light remains on all the time, your ABS system has a fault and has disabled itself. This means your ABS system cannot intervene if you need it during a hard panic stop or when braking on a slick road.

* Check your wipers. If the blades are chattering or streaking, or the rubber is cracked or torn, replace the wiper blades. Replacing the wiper blades yearly is a good idea.

* Check your lights. Make sure all the lights work, including the brake lights and turn signals.

* If your steering feels loose, the steering wanders while driving straight or pulls to one side, have your steering linkage and suspension inspected for worn or damaged parts.


Maintaining your vehicle means paying attention to the tires, brakes, steering and other safety systems to make sure your vehicle is safe to drive. Here are some problems you should watch for:


A study conducted by Indiana University way back in 1977 estimated that 1.4% of all auto accidents could be attributed to underinflated tires. When a tire is underinflated by more than 25%, it greatly increases the risk of the tire overheating and failing, especially when driving at highway speeds during hot weather. This study, along with a rash of fatal Ford Explorer rollover accidents caused by tire blowouts (which Ford blamed on poor quality Firestone tires, and Firestone blamed on drivers not keeping their tires inflated properly, overloading their vehicles, and/or driving too fast during hot weather) lead to the passage of the TREAD Act, which now required Tire Pressure Monitoring Systems on all vehicles as of model year 2008.


tire blowout When the tread on a tire is worn down to 2/32 inch (16 mm), there is not enough tread left to provide safe wet traction. So when the tire hits a puddle on the road, there isn't enough groove depth left to handle the water. The water forms a wedge under the tread and literally lifts the tread off the pavement. This is called hydroplaning, and it is a potentially dangerous situation because the tire is no longer in contact with the road. It is skimming over the water with no directional stability or traction whatsoever. Under these conditions, the vehicle may lose control and spin if the vehicle is turning, accelerating or braking. If the vehicle is equipped with stability control, the stability control system may help the driver maintain control provided some of the other tires still have traction. But if all of the tires are badly worn and are hydroplaning on a wet surface, you vehicle essentially becomes a hockey puck. Under these conditions, the only thing you can do is to lift your foot off the gas pedal and/or brake pedal, and avoid making any jerky or abrupt steering maneuvers. When the vehicle slows and starts to regain traction, gently brake and reduce your speed.

The condition of the tires should be inspected regularly. Look for unusual or uneven wear, bulges or wrinkles in the tire sidewalls, cracks in the tread that may indicate tread separation, or loss of air pressure. A small puncture in the tire or a rim leak where the tire bead seals against the lip of the wheel could lead to a flat tire or a blowout.


Brake pads and shoes are wear items and have a limited service life. The more you drive and use your brakes, the more the brake linings wear. Eventually, they wear down to the point where they have to be replaced.

The hydraulic and mechanical components in your brake system also have a limited service life. Over time, rubber seals and hoses can deteriorate and leak. Metal components can rust and corrode. If your brake system develops a leak, it may cause the brakes to fail because of loss of hydraulic pressure when you apply the brakes.

Check your brake fluid regularly. The fluid level in the master cylinder reservoir will gradually drop as the brake linings wear. But if the level suddenly drops, it may indicate a leak and a need for immediate brake repairs.

Symptoms of worn brakes include scraping metallic noises when you apply the brakes, a pull to one side when braking, a soft or spongy feeling brake pedal, a low brake pedal, or a peal that slowly sinks to the floor when you are holding pressure on the pedal at a stop light. Any of these can create a potentially dangerous situation, so don't neglect your brakes if you think they need attention.


suspension failure The tie rod ends in the steering linkage will wear over time, and loosen up. This can cause looseness and play in the steering, which you can feel when you are driving. Your vehicle may also tend to wander when driving straight. The danger here is if a tie rod end fails and pulls apart. This can happen when the tie rod socket is badly worn and the ball stud pulls loose.

If a tie rod end fails, you will lose steering control of your vehicle. The wheel on the side with the separated tie rod end will immediately be pushed as far back as it will go, causing the vehicle to veer sharply in that direction. If the left tie rod fails, that could pull you across the centerline of the highway into the path of oncoming traffic.

To prevent this from happening, the tie rod ends should be inspected if your tires show unusual or repaid wear, or if the steering feels loose. The tie rod ends should be checked for any visible play, or play that exceeds specifications. If the tie rod end is loose or worn beyond specifications, it must be replaced.

NOTE: The tie rods on most late models are sealed for life and cannot be lubricated. On older vehicles, grease fittings were provided so the joints could be lubricated when the engine oil was changed.

Another component in the steering linkage that may need to be inspected is the flexible coupling between the steering column and steering gear or steering rack. If this coupling becomes worn and separates or breaks, you will lose all steering control. The coupling is located at the base of the steering column.


broken ball joint causes wheel to fall off The ball joints connect the control arms to the steering knuckle. Cars with MacPherson struts typically have two lower ball joints (one on each side, while those with Short Long Arm (SLA) suspensions have four joints (one upper and one lower ball joint on each side). As the ball joints wear, the ball stud can become loose in the socket, increasing the risk of stud breakage or separation. If the ball joint fails, the suspension on that side will collapse causing a loss of steering control.

Ball joints should be inspected if the tires show uneven wear (typically heavy shoulder wear on the inside of the tire or tires), or you hear clunking noises when driving and you hit a bump. Some ball joints have wear indicators to show if the joint is good or bad. Others require measuring to determine if play exceeds specifications. Worn ball joints should be replaced if wear exceeds specifications or wear limits.

NOTE: The ball joints on most late models are sealed for life and cannot be lubricated. On older vehicles, grease fittings were provided so the joints could be lubricated when the engine oil was changed. On some trucks, the joints still have fittings (or aftermarket ball joints with grease fittings may have been installed). If this is the case, the joints should be lubricated every 6,000 miles to extend their life.


The lug nuts keep the wheel on the hubs. As long as the lug nuts are tightened properly to specifications when a wheel is changed, they should remain tight and not work loose. But if the lug nuts are not tightened adequately, they may loosen up over time and allow the wheel to fall off.

Lugs nuts should be tightened with the wheel on the ground and the weight of the vehicle on the tire. The nuts should be tightened to specifications (typically 60 to 80 ft. lbs.) in an alternating star pattern using a torque wrench.

Installing the wrong type of lug nuts for the type of wheels on the vehicle may also prevent the nuts from retaining torque properly, allowing them to loosen up.

A wheel that has one or more damaged lug nut holes may not allow the nuts to retain torque. This can result from over-tightening the lug nuts with an impact wrench. A damaged wheel must be replaced.


Wheel bearings and axle bearings on late model vehicles are usually sealed assemblies and require no maintenance. Under normal driving conditions, they should last upwards of 200,000 miles with no problems. But sometimes outside contaminants can enter a wheel bearing (as when driving through hub-deep water or mud) and cause the bearing to fail. Extreme loading or abusive driving can also increase the load on the bearings and shorten their life.

If a wheel bearing is failing, it will often produce a cyclic noise that changes with vehicle speed. It may also produce a slight growling or rumbling vibration that can be felt in the vehicle. A noisy or rough bearing should be inspected without delay.

If a wheel bearing or axle bearing fails, it may cause the vehicle to lose a wheel, which also means loss of steering control.


bad defrosters reduce visibility Defrosters that do not work can make it difficult to see on a cold, wet day. The defrosters should direct air to the windshield when they are turned on. If your heater/air conditioner controls have a RECIRC or OUTSIDE air button, use the OUTSIDE air option. Using RECIRC will only recirculate the wet, moisture laden air and make matters worse.

When the defrosters are turned on, the air is usually dehumidified by the air conditioner to make the water on the inside of the windshield evaporate more quickly. If your A/C is not working, this obviously won't happen. If the heater fan blower is not working, no air will blow out of the defroster ducts. If the door that redirects the air from the heater outlets to the defroster outlets is stuck or inoperative, the defrosters won't work. Or if the ductwork that connects the defroster outlets to the HVAC unit is loose or leaking, air may not find its way to the defroster outlets.


If you are driving an old car that has a badly rusted chassis, there is a chance that the strut towers or other suspension attachment points may break loose or collapse. Cars are not designed to last forever, so if you are driving a old rust bucket, you should keep a close eye on the load bearing points like the strut towers, subframe and other suspension attachment points.


Vehicle manufacturers build millions of cars and trucks every year. They all use various quality control procedures (such as QS9000) to assure their vehicles meet quality expectations and are safe to drive. But every now and then, a batch of bad parts may slip through the screening process and cause problems for motorists.

Any defective part that affects steering or braking could potentially cause an accident. A defective steering or suspension component that breaks and causes loss of steering control would certainly be a contributing factor if the failure resulted in an auto accident. The same goes for a defective brake component that prevented the brakes from stopping the vehicle safely. This reasoning would also apply to tires that blowout or fail due to tread separation, or other structural or manufacturing defects.


justice symbol In situations like these, there may be grounds to sue the vehicle or parts manufacturer, especially if the parts defect or failure resulted in personal injury or death. You would have to show proof that a defective part contributed to or caused the accident. That means having the physical evidence (the defective or failed part), an expert evaluation of what caused the accident, and a police report verifying the details of the accident.

Truck accidents, in particular, can be very dangerous because of the huge weight difference between a car (3500 to 4500 lbs.) and a large truck that may weigh up to 80,000 lbs. or more when fully loaded. If a truck or its trailer has not been properly maintained, it may be a rolling accident waiting to happen. A tire blowout, brake failure, steering or suspension failure could cause the driver to lose control. An attorney experienced in these kind of issues can help you establish your case if a mechanical defect played a role in your accident or injury.


There have been some issues over the years with some antilock brake systems causing loss of braking on certain vehicles, namely Ford and GM pickup trucks with Kelsey-Hayes rear-wheel RABS or RWAL brakes. What often happens is that the valve in the ABS accumulator sticks open because of corrosion or residue in the brake fluid. When the driver hits the brakes, the pressure goes into the accumulator instead of to the brakes, causing the pedal to go to the floor. The vehicle doesn't stop. Some would argue this is a manufacturing defect, but others would say it is due to a lack of maintenance (not changing the brake fluid every four or five years to reduce the risk of corrosion inside the brake system).

truck crash Brakes have also been known to fail when the get too hot. Driving down a steep mountain can cause a lot of heat to buildup in the brakes. Eventually the point may be reached where the pads get so hot they not longer produce enough friction to slow the vehicle, and braking is lost. Or, the brake fluid in the calipers may get so hot that it starts to boil, causing a loss of brake pedal. Both conditions are due to the driving conditions the brakes are being subjected to, but it can also be argued that the brakes may not have been designed with enough reserve cooling capacity to minimize the risk of this happening. rotors that are not large enough or lack adequate venting may not provide enough cooling under severe driving conditions. Brake pads that do not have a high enough hot coefficient of friction may fade at high temperature. Brake fluid that does not have a high enough boiling point or is contaminated with moisture may boil if it gets too hot.


Tire blowouts can be caused by running over a sharp object in the road that punctures the tire, a leaky valve stem that fails to keep air inside the tire, hitting a curb or pothole that damaged the tire, improper tire inflation (not enough or too much air in the tire), driving too fast for the speed rating of the tire, using tires that do not have an adequate load rating for the vehicle application, and structural and manufacturing defects in the tire or wheel.

A tire is actually a rather complicated component to manufacture. There are belts and reinforcing cords inside the tire, various layers of rubber and tread, and it all must be mixed and cured at the right temperature for the tire to perform as designed. If a mistake is made during the manufacturing process, and the flaw is not discovered when the tire is inspected, the manufacturing defect may cause the tire to fail when it is installed on a vehicle. Such defects include tread cracking and separation, air leaks and belt failures.

If you have a low mileage tire that is losing chunks of tread, cracking or bulging, it probably has a manufacturing defect. Go online and check for tire recall notices that may apply to your brand of tire. If there has been a recall, get the defective tires replaced ASAP.

Tires have a wet and dry traction rating on the sidewall, a temperature rating, a wear rating, a speed rating, a load rating, a maximum inflation pressure (which must not be exceeded), and a manufacturing date code. All of these should match the vehicle application as well as the vehicle owner's expectations and driving requirements.

If you have a high performance sports sedan, you should have speed rated tires on it. Likewise, if you drive a large pickup truck and haul heavy loads, the tire load ratings should equal or exceed your maximum payload. If you do a lot of high speed hot weather driving, the temperature rating should be an "A," not a "B" or "C". If you do a lot of wet weather driving, you should have "All-Season" tires with an "A" wet traction rating.

Driving on the "wrong" tires increases your risk of a tire failure and an auto accident.

mechanical causes of auto accidents More Auto Safety Articles:

Recalls Don't Ignore Them!

Car Fires

Toyota Unintended Acceleration: Possible Causes

Safe Travel Trips

Distracted Driving Poses Safety Risk

Drunk Driving Accidents

Why I'd Rather Drive than Fly

Watch Out For Old Tires

Why Tires Fail

Preventing Tire Failures

New Tire Pressure Monitoring Systems (TPMS)

Tire inflation tips

Blame It On The Tires

Tire Wear (What to look for, how to reduce it)

How To Inspect Your Car's Suspension

How Shocks & Struts Affect Vehicle Stability, Handling & Safety

Fixes For Common Brake Problems

No Brakes!

Brake Fluid: A Hot Topic

Be sure to visit our other websites:
auto accident

AA1Car Automotive Diagnostic & Repair Help

Auto Repair Yourself

Carley Automotive Software