Monthly Archives: November 2010

Common Brake Problems and Maintenance

Your brakes are easily one of the most important components of your car. Having well-maintained and effective brakes will go a long way towards keeping you safe on the road! Few things are more terrifying than jamming on the brakes in an emergency and finding they don’t work. Before reading further, it may be helpful to check out a previous entry on how brakes work. This will help you to understand some of the problems discussed here.

Should you experience brake failure, there are a few things you can do to slow down your car and minimize potential damage; check out these tips.  However, this situation is best avoided altogether!

First, practice good driving techniques to avoid putting excess wear on your brakes. Regularly braking hard—“slamming on the brakes”—puts a great deal of strain on your brakes. Driving in stop-and-go traffic also exacerbates brake wear; if possible, try to arrange your schedule so as to avoid the worst of rush hour. While driving, don’t “ride” the brake pedal or let your foot rest on it. Also, coasting to slow down before braking can help to save your brakes. Try to plan ahead; slow down if you see cars braking ahead. Look down the road a ways to spot other hazards, stop signs, and red lights that may be coming up in your path. Also avoid carrying excess weight in your car, as this will put extra strain on your brakes. Note that several of these strategies will also help you to save gas! Finally, there are different grades of brake shoes and brake pads. While the lower grade pads are cheaper initially, they will wear out faster and often don’t perform as well. Purchasing the higher grade pads and shoes will be more cost-effective in the long run and will reduce wear on the other components of your brake system as well.

Next, pay careful attention to the feel of your brakes when braking and the sound they make. Unusual noises and feelings can be symptoms of brake problems. Here are some of the most common problems and their causes:

Brake warning light comes on: This most likely indicates that there is a leak in the system. Don’t drive until you have had the system checked out, and any leaks have been repaired.

Brake pedal “rests” at a lower position: This is usually caused by drum brake adjusters not working properly. If the adjusters are rusty or they stick, they won’t advance properly. In addition to having the brakes readjusted, you will need to have the adjusters cleaned or replaced. This could also indicate that the brake pads or shoes need to be replaced or that there is a leak in the system.

“Spongy” brake pedal: If your brakes are “soft,” i.e. the pedal doesn’t offer as much resistance when you push it, then there is likely air in hydraulic system somewhere. Your mechanic will need to “bleed” brake lines, i.e. drain and replace the oil.

Need to push pedal too far in: This could be due to a variety of problem: worn brake pads or shoes, poorly adjusted drum brakes, or air in the lines. You can pump the pedal several times to compensate for this, but you will still need to get your brakes checked as soon as possible.

Pedal pulses or vibrates when you brake: This occurs when the rotors on the disc brakes, which should be flat, are worn unevenly. As a result, they don’t make contact evenly with the pads, which then causes vibrations. The rotors need to be resurfaced or, if the problem is severe, replaced.

A scraping noise: This occurs when there is metal to metal contact in the brakes, which means that you have worn entirely through the brake pads or shoes. A brake servicing is long overdue! Driving with shoes or pads this worn can seriously damage your brakes, forcing you to replace more expensive parts in your brakes.

A squealing noise: This can be caused by vibrations between the brake pads and rotor or caliper. This may be unavoidable on some older brakes which use semi-metallic compounds in the pads. Replacing the brake pads with newer ones can help. There are a few other strategies your mechanic can use to minimize this noise. However, this could also be a more serious problem, such as worn brake pads or a missing gasket, so do get your brakes checked soon.

A jerky, “slip-and-grab” feeling: It’s likely that brake oil or another substance has leaked onto to the brake mechanism. Contaminated pads will need to be replaced and, of course, the source of the contamination has to be identified and stopped.

Pedal sinks to the floor: This occurs when pressure isn’t being maintained in the hydraulic system. This is likely a leak or a worn-out master cylinder. Don’t drive in this situation! Instead, have your car towed and fixed immediately.

Brakes don’t release properly: There are several potential causes: the springs in the drum brake are not working properly; the floating caliper in the disc brakes isn’t adjusted correctly; the emergency brake cable or mechanism is broken; or the adjuster mechanism in drum brakes has extended too far.

Car swerves to one side when brakes are applied: This means that braking power isn’t evenly distributed between the front brakes. The car will “draw” to the side with the stronger brake, as the opposite wheel now has greater driving power. It’s likely that a leak, broken piston, stuck caliper, or other mechanical failure has occurred in one of the brakes. This can also be caused, however, by different brands of brake pads being used on the two front brakes, as different makes of pad and compounds have different braking properties.

Brakes are hard or difficult to use: Usually this means that the vacuum assist isn’t working properly, forcing you to put a lot more power into the system. The booster itself could be leaky or defective, or the check valve could be failing. You can test the check valve by running the engine for a few minutes (building vacuum) and then turning off car. If you don’t have power assist after a few minutes, the check valve is broken. To test the vacuum booster itself, turn off the engine. Pump the brake pedal a few times to “bleed” all remaining vacuum from the booster. Then, restart the engine and let it run for a couple of minutes. This should build vacuum in the booster again. Now, try your brakes. If there’s no power assist, this means that the vacuum booster is broken.

ABS Warning light comes on: This means that the computer has detected a problem in this system and turned it off. While this isn’t going to put you in immediate danger, it’s still better to have this system checked sooner rather than later.

Brakes lock: This is likely caused by a damaged brake pad or shoe. Have your car towed immediately.

In addition to listening for problems like these, you should also check your brake system periodically in order to stop problems before they happen. First, check the level of brake fluid in the reservoir often. If necessary, top up with fluid as needed; if the level of fluid seems to be sinking quickly, have your mechanic check for a leak.

Have your brake pads checked regularly and changed as needed. How often you will need to do this depends a lot on your driving habits and the car you drive. In general, brake shoes will need to be replaced after four rotations of brake pads.

Finally, take a moment from time to time to check that your brake lights are working.

 You should have a thorough “brake job” done either when the pads are worn down or if you notice any of the symptoms above. Your mechanic will carry out a variety of routine maintenance tasks, including replacing the front pads, resurfacing the rotors, replacing the shoes (if needed), resurfacing the brake drums, bleeding the brake lines, checking for leaks, and checking and adjusting the parking brake.

More comprehensive maintenance will also include new hardware for drums—springs in particular age with exposure to heat and should be replaced—and the of rebuilding wheel cylinders and calipers.

To read more on a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!

Check out these sites for more information about defensive driving and business driver safety.

Advertisements

HOW DO BRAKES WORK? Part 3 – Power Brakes and Antilock Brakes

Power Brakes

While drum brakes provide some additional power assist, as we saw in the discussion in Part 2 of this series, disc brakes don’t. In most cars with disc brakes, additional force multiplication is needed in order to make the brakes effective and easy to operate. This power is provided by the vacuum booster; cars that use a vacuum booster are said to have power brakes.

The vacuum booster—a large, flat cylinder—is easy to locate in the engine. (See Figure 10)

 

Figure 10: a vacuum booster

As you can see, the vacuum booster is connected directly to the master cylinder. A hose also connects the vacuum booster to the engine via the check valve. The engine, which generates vacuum naturally as it functions, removes air from the vacuum booster, while the check valve ensures that air doesn’t enter the vacuum booster when the engine shuts off.

The vacuum booster uses vacuum power to increase the force provided by the brake pedal. A shaft passes directly from the brake pedal, through the vacuum booster, to the master cylinder (Figure 11).

 

Figure 11: Inside a vacuum booster

As you can see, there is a diaphragm inside the vacuum booster that separates the end of the booster nearest the master cylinder from the side nearest the brake pedal.

When the brake pedal is released, an ingenious one-way valve opens inside the vacuum booster, connecting the two halves of the booster. This allows the engine to remove air from both halves of the booster, creating a vacuum throughout.

However, as soon as you depress the brake pedal, this valve closes, separating the two sides. At the same time, the front end of the booster opens, allowing air into the front half of the chamber. This creates a difference in pressure between the two halves of the booster, as the air will be at atmospheric pressure on the one side of the diaphragm, while there is no air pressure in the vacuum. As a result, the pressure of the incoming air pushes the diaphragm towards the back of the booster. The diaphragm is connected to the shaft that leads to the master cylinder, so that the force of this push is transmitted to the brake lines via the master cylinder. This process provides a great deal of power; with power brakes, almost anyone can stop a vehicle of any size with ease.

Anti-Lock Brakes

Many modern cars also contain anti-lock brakes, which further help to increase braking effectiveness and safety.

As we discussed above, wheels will “lock-up” and cause a skid if too much braking force is applied too quickly. However, you get maximum braking power just before the wheel locks. For this reason, in order to stop suddenly, especially in wet conditions, you need to approach this threshold without exceeding it.

This is where anti-lock brakes come in. Using a set of speed sensors, the anti-lock brake system’s computer controller can detect when one wheel begins to move slower than the others, i.e. when it is about to lock. At this point, the anti-lock brake controller sends a signal to a valve attached to that wheel’s brake line, which closes to prevent further pressure from being applied. The valve also releases pressure from that wheel. When the tire is no longer decelerating, the valve returns to its starting position, and a pump restores pressure to that wheel.

All of happens very quickly; the system can cycle through this process up to 15 times a second! In some cars, the rapid opening and closing of these valves will produce a “pulsing” feeling in the brake pedal. While this can be disconcerting, it is actually a sign that your anti-lock brake system is keeping your safe.

 Read Part 1 of this series to learn about brake basics. 

To read more on a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!

Check out these sites for more information about defensive driving and business driver safety.

HOW DO BRAKES WORK? – Part 2: Disc Brakes and Drum Brakes

Disc Brakes

While there are several different kinds of disc brakes, the most common is the single-piston floating caliper. You’ll see what this means in a minute. This kind of brake has three main components: the brake pads, the caliper, and the rotor. (See figure 8.)

 

Figure 8: a disc brake

The brake pads are the rough friction surface that is pressed against the rotor to stop the wheel. The rotor is a round plate attached to the hub. The piston presses one brake pad against the wheel, while the caliper presses the other. The caliper is “floating” because it moves in a track that allows it to center itself over the rotor. As the brake fluid fills the cylinder, it pushes the piston to the left; however, it also pushes the caliper to the right. This allows both brake pads to press against the wheel simultaneously. Note that the brake pads don’t actually retract away from the rotor when the piston is released. Rather, they continue to press lightly against the rotor.

Remember that brakes produce a lot of heat. As a result, it’s important that the whole system be vented. Additionally, rotors are constructed with internal vents that dissipate heat. While once made of asbestos, brake pads today are made from various combinations of organic, metallic, and ceramic compounds.

Disc brakes are far more effective than their cousins, drum brakes. However, disc brakes are more expensive to manufacture and need to be made and aligned more precisely. If they come out of alignment, you’ll notice a dramatic shuddering when you brake. For this reason, many cars use disc brakes only on the front brakes. They then use drum brakes on the rear wheels. While drum brakes have more parts and are harder to service, they are cheaper and can easily accommodate an emergency brake mechanism.

Drum Brakes

Like a disc brake, a drum brake uses friction to stop the car. The drum brake is also activated by pistons; in this case, the pistons cause two curved brake shoes to press against the inside of an iron drum, which is in turn located inside the wheel (See Figure 9).

 

Figure 9: Drum brake

Notice, however, that the system is slightly more complex than a disc brake. When the pistons activate the drum brake, the top edge of the brake shoe is the first part to contact the spinning drum. The spinning motion of the drum then pulls the brake shoes outward further, increasing the force with which the shoes press into the drum. As a result, the pistons on a drum brake can be smaller than those on a disc brake.

When the brake is released, the springs in the drum brake pull the shoes away from the drum again; otherwise, the wheels would be unable to spin due to the “pulling” action of the drum against the brake shoes. When driving in reverse gear, the opposite happens, i.e. the bottom part of the brake shoe is pulled against the drum.

As in a disc brake, the brake shoes will wear down over time. A drum brake compensates for this wear by means of an adjuster mechanism.  This mechanism has two parts: a gear that is threaded onto a shaft, like a screw, and a lever (orange in the diagram) which is attached to the brake shoe.

When the car stops in reverse, the lever pulls against the adjuster as the drum pulls the bottom part of the shoe tight against the edge. If the gap between the brake shoe and the drum is too big, then the lever will pull the adjuster enough for it to slide forward a notch, lengthening the adjuster shaft. This pushes the bottoms of the brake shoes outwards, making the gap between shoe and drum smaller.

As you can see from the diagram above, it’s easy to add an emergency brake mechanism to a drum brake. Most emergency brakes are activated by a cable and lever system, like the one pictured above.

While disc brakes can incorporate emergency brakes, these systems are usually more complicated and expensive. In cars with only disc brakes, a second mechanism must be added to the brakes to accommodate the emergency brake function. This can take the form of a second, modified caliper system OR a kind of drum brake, built into the disc brake system.

The Combination Valve

It therefore makes sense to use a combination of disc and drum brakes in a car. Remember, however, that the disc brakes are always in contact with the rotor, while the drum brake shoes are pulled away from the drum walls. For this reason, the drum brakes need to move further in order to make contact with the wheel. In cars with both disc and drum brakes, the metering valve helps to compensate for this difference. The metering valve only allows pressure through to the disc brakes when a threshold pressure is reached. This means that power first goes to the drum brakes. However, the threshold is usually fairly low, so that the disc brakes engage only a little bit after the drum brakes. 

The metering valve is one part of a combination valve, which contains several other valves as well.

The proportioning or equalizer valve accounts for the fact that there is a greater force on the front wheels when you stop. Bear in mind that wheels can only take so much force before they “lock up,” i.e. stop spinning. For this reason, jamming on the brakes too suddenly can cause you to go into a skid. In order to keep the back wheels from locking when more pressure is applied to the front brakes, the proportioning valve insures that more pressure is transmitted to the front brakes than the rear brakes.

The pressure differential valve is used to detect leaks in the braking system. This valve consists of a piston inside of a cylinder. Each side of this cylinder is then attached to one side or the other of the master cylinder. Pressure should thus be equal on both sides of the piston, keeping it in place. If the pressure changes, then the piston will move to one direction or the other. This activates a switch, which causes a brake warning light to turn on in the dashboard.

Read about Brake Basics in the first part of this series.  Read about Power Brakes and Antilock Brakes in the third part of this series.

To read more on a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!

Check out these sites for more information about defensive driving and business driver safety.

HOW DO BRAKES WORK? Part 1 – Braking Basics

Braking seems fairly simple: you press a pedal and the car stops. If you’re like me, you never really thought twice about how a small motion in your foot can stop an entire car. However, braking systems are elegant, ingenious, and complicated systems. With the help of a few basic principles of physics, the smallest exertion on your part can be magnified into enough force to stop a car.

Like so many systems in your car, your brakes run on a hydraulic system. In a hydraulic system, pressurized fluid passes through tubes, cylinders, and the like to transmit force from one place (the pedal) to another (the brake device.) Cars use different kinds of brakes: drum, disc, and power brakes. Many cars use a combination of brakes, with drum brakes on the rear wheels and disc brakes on the front. I’ll discuss each of these different kinds of brakes in detail below. First, however, I want to start by explaining the basic principles that make brakes possible.

Braking Basics

The force of your foot stepping on the brake pedal isn’t, by itself, enough to stop your car. As a result, your braking system needs to multiply the force that you put into the system, so that a greater force will be produced at the braking device. This is accomplished through the application of leverage and hydraulic force multiplication.

The brake pedal operates as a lever, a device in which a plank or rod is connected to a pivot. (See Figure 1) When force is applied to the “long” side of the lever, a greater force is produced in the opposite direction on the “short” side.

 

Figure 1: A simple lever

As you can see from the diagram, the increase in force is directly proportional to the decrease in distance. If the long side of the lever is twice as long as the short side, then twice as much force will be produced on the short side.

In a car’s braking system, the lever attached to the brake pedal multiplies the force produced by your foot before transmitting this force to the hydraulic system, where the force undergoes further multiplication.

A hydraulic system, such as the one that powers your brakes, uses an incompressible fluid. This means that, when force is applied to this fluid, it can’t become denser. Instead, it has to move from one place to another. In the case of brakes, this fluid is a special kind of oil that won’t boil at high temperatures or thicken at low ones. Brake fluid is stored in a special reservoir on top of the master cylinder, a device I’ll discuss below. (See FiFigure 2: Brake fluid reservoir and master cylinder

Essentially, the hydraulics in your brakes work a bit like a giant syringe: when you apply pressure to a piston at one end, the fluid transmits the same pressure to a piston at the other end. (See Figure 3)

 

Figure 3: basic hydraulic system

When I push the piston on the left cylinder down by a certain amount, the piston in the cylinder on the right will move up by the same amount. The force is transferred from the left piston to the right piston, although the directions are reversed—a bit like in a lever.

However, you don’t need to have one “input” cylinder for every “output” cylinder; if this were the case, you need to depress four brake pedals instead of one. In the brakes’ hydraulic system, a single “master cylinder” can be used to transfer power to several “slave cylinders.” (See Figure 4)

 

Figure 4: “master” and “slave” cylinders

Note also that the pipes or tubes connecting the cylinders can be as long, twisted, and winding as they need to be in order to snake from the brake pedal to the wheels; the force will be transmitted through the fluid just the same.

So, how does this system multiply force? Bear in mind the idea that force and distance can be interchangeable. If I apply a certain force over a long distance, I am applying a greater cumulative force than I would if I applied the same force over a shorter distance. As a result, if we depress the piston in the first cylinder further but don’t allow the second cylinder to rise by the same amount, then we will produce a greater force in the second cylinder. (See Figure 5)

 

Figure 5: hydraulic force multiplication

As you can see from the image above, this is accomplished by making the first cylinder much narrower in diameter than the first. We can depress the first piston to the bottom of the cylinder; however, this will only transmit enough fluid to raise the second piston a fraction of the way up its cylinder. As a result, the upwards force on the right will be much greater than the downwards force on the left.

When this hydraulic system is combined with the lever system, you can achieve a great deal of force multiplication. (See Figure 6)

 

Figure 6: a simple brake system

In this system, the distance from brake pedal to the pivot is four times the distance from the piston head to the pivot. (Note that both “outputs” can be on the same side of the pivot, which allows you to have your input and output forces going in the same direction.) This increases the input force by a factor of four.

Next, notice that the diameter of the input cylinder, Y, is one third of the circumference of the brake cylinder (output.) This multiplies the force by nine. Taken together, this system produces an output force that is 36 times greater than the input force!

Now, how does this force translate into the car stopping? In order to answer this question, we need to look very briefly at a couple other ideas from high school physics. Remember that energy isn’t destroyed; rather, it changes from one form to another. When a car is moving, it has kinetic energy. In order to stop the car, we need to turn this into another kind of energy. The brakes convert the car’s kinetic energy into heat, or thermal energy.

They do this by applying friction to an element in the car’s wheels. Friction is the property of objects that makes it difficult (or easy) to slide one thing across another. While many surfaces look more or less smooth to us, all contain roughness at a microscopic level; when surfaces rub together, these microscopic peaks and valleys “catch” against one another, producing heat. The “rougher” something is, the higher its coefficient of friction will be. A car’s brakes contain material that is very “rough,” i.e. has a high coefficient of friction. This allows the brakes to turn kinetic energy into heat energy pretty quickly.

The Master Cylinder

Before we move on to a discussion of different kinds of brakes, let’s take a moment to consider what happens if this system develops a leak. The brakes would fail very quickly. Because driving is such a high-risk activity (and because brakes are so crucial for driving safety), it’s important that this hydraulic system have a safety or back-up system built into it. This is accomplished through an ingenious design for the master cylinder. (See Figure 7)

 

Figure 7: master cylinder

Notice that this system has two reservoirs of brake fluid and two lines going to the brakes. When you push the brake pedal, it applies force to the first piston, which pushes the fluid down the first brake line. The springs then transmit power to the second piston, which pushes the fluid into the second brake line.

Now, say that you develop a leak somewhere in the first brake line. This system won’t produce any pressure. However, the first piston will still transmit power to the second piston through the springs, so that the fluid in the second brake line will be compressed. The opposite will happen if a leak occurs in the second brake line. Of course, if there is a leak, your brakes won’t be as effective; you’ll probably notice that you have to push harder on the pedal in order to produce a lesser amount of stopping power. However, your brakes will still function, which wouldn’t be the case without this clever double-barrel design.

The master cylinder is connected to another complex device called a combination valve. I’ll discuss this a bit later; first, read on to Part 2 of this series to review the two basic brake types: disc brakes and drum brakes.

To read more on a broad range of subjects from “How To Change A Tire” to “How To Jumpstart Your Car”, visit DefensiveDriving.com’s Safe Driver Resources website!

Check out these sites for more information about defensive driving and business driver safety.

Accident Liability: Who Is At Fault?

Now that I’ve discussed what to do if you’re in an accident, it makes sense to look at what happens after an accident. Car accidents can be very costly, both in terms of personal injuries and damage to your car. Understanding how insurance companies determine fault and what you are legally liable for can help you to avoid paying unnecessary damages.

At first glance, the laws and regulations surrounding liability for motor vehicle accidents can seem daunting, particularly because legal jargon is pretty opaque. However, the basic principles are fairly simple and logical.

First off, insurance companies need to determine who is at fault in an accident, as this will impact who is awarded damages and how much payment each party receives. Under common law, there are different kinds of fault. The two most commonly applied to car accidents are negligence, which is careless or inadvertently harmful behavior, and recklessness, which involves a deliberate disregard for the safety of other people. Failing to observe the proper procedure at a four way stop would be a case of negligence, while drunk driving would constitute reckless behavior.

One more useful piece of vocabulary before we move on: If you cause an accident, you have committed a tort, which is a private wrong committed outside of a contract. Someone who commits a tort is called a tortfeasor. You may notice this language in your insurance policy, but don’t let it intimidate you.

 After you’ve submitted your insurance claim, your insurance company will negotiate with the insurance company of the other party or parties on your behalf. Together, the companies will decide what is fair compensation for each party.

Insurance claims adjusters look at four factors in order to determine fault: duties, breach, causation, and damages. All four of these elements need to be in place in order for the company to assert that a party is at fault.

First, every driver has certain duties while on the road. These duties are usually described as “look out,” avoidance, and following the rules of the road. “Look out” means that you need to be aware of your surroundings at all times. It’s your duty to see what is happening on the road and in your environment. For this reason, never tell an adjuster or police officer that you “didn’t see the other car” or “it came out of nowhere.” This is enough to establish that you are at least partially at fault, as you didn’t uphold your duty to be aware of your surroundings.

Avoidance means that you have to do your best to avoid the accident. This doesn’t mean that you have to actually avoid the accident, it just means that you have to demonstrate that you tried. For example, if a car runs a red light as you are entering an intersection and you don’t brake or swerve to avoid hitting that car, then you are partially at fault, even though the other driver broke the law. The third duty, following the rules of the road, is fairly straightforward.

In order to determine fault, insurance companies need to show that you have failed in one of these duties. This is known as a breach. They also need to show causation, i.e. that there is a connection between the duty breached and the damages caused. All damages, either property damages or injuries, must be related to the duty breach that you caused. For example, say that your car is parked with the engine running, but you are not wearing your seatbelt; another car hits you, and you are injured in the collision. On the one hand, you were breaking the law by not wearing your seatbelt. However, this breach did not cause the accident, i.e. wearing your seatbelt would in no way have ameliorated this accident. Therefore, you are not liable for damages to either car. However, if failure to wear the seatbelt exacerbated your injuries, your claims for these damages due to personal injury could be reduced.

In order to make these determinations, insurance companies rely on the police report and other accounts of the accident. In making your claim, it may be helpful to review the police report yourself and to check up on local law codes regarding the driving situation you were in. If you can cite a specific code that the other driver broke, you will be going a long way towards helping your insurance company prove the other side was at fault.

There are two kinds of accidents where fault is pretty straightforward. The first is a rear end accident. In this instance, the driver behind you is always at fault, as he or she has a clear duty to maintain a safe following distance. Even if you stop suddenly, the other driver should have enough space to stop safely as well. If that driver has been pushed into you by another car, he could claim damages from the car that hit him. However, he is still liable for the damages to your car. If you’ve done something wrong, such as driving without working brake lights, your damages award could be reduced.

The other case is a left turn accident. In this scenario, the driver turning left is at fault, as the driver going straight has the right of way. There are a few exceptions, of course, such as if the other driver is speeding or runs a red light.

In most other types of accidents, there will most likely be some degree of fault on both sides. In these cases, the way that fault is handled varies from state to state. Four different kinds of laws are in place.

In states with contributory negligence laws, if either party is at all at fault, then they cannot claim damages. Even if you are only slightly at fault for an accident, you will not be able to claim any damages. Only a few states follow this law: Alabama, District of Columbia, Maryland, North Carolina and Virginia.

Another, more common kind of law, is pure comparative fault. Under this law, your damage award is reduced by your percentage of fault. If you are 10% at fault, then your award will be reduced by 10%. New York, Rhode Island, Kentucky, Mississippi, Louisiana, Florida, California, Missouri, New Mexico, Arizona, South Dakota, Washington and Alaska use this law.

Other states use proportional comparative fault. This means that if you are above a certain percentage at fault, you will not be able to claim damages. Some states set the bar at 51%, so if you are found to be 51% or more at fault, you cannot claim damages. These states include Connecticut, Delaware, Hawaii, Illinois, Indiana, Iowa, Massachusetts, Michigan, Minnesota, Montana, Nevada, New Hampshire, New Jersey, Ohio, Oregon, Pennsylvania, South Carolina, Texas, Vermont, Wisconsin and Wyoming. Other states set the bar at 50%, so that if you are 50% or more responsible, you can’t claim for damages. States using this law are: Arkansas, Colorado, Georgia, Idaho, Kansas, Maine, Nebraska, North Dakota, Oklahoma, Tennessee, Utah and West Virginia.

Once fault is determined, the next step is to assess the total cost of all damages. For this reason, it is important that you keep records of any expenses related to the accident. This is also why it is essential that you receive a medical check-up shortly after the accident, even if you do not think you are seriously injured. If a more serious problem does manifest itself in the weeks after the accident, it can be become increasingly difficult to prove that this problem was directly caused by the accident. Damages in the form of lost wages and loss of future earnings are also taken into account, as are general damages, such as pain and suffering or reduced quality of life, although these can be more complicated. In the case of a particularly severe or complicated accident, it could be a good idea to consult a lawyer, as these cases can become very complex.

Finally, it always helps to be familiar with your insurance policy and the liability limits. Note that there will be two separate limits for injury and property damages. Purchasing personal injury protection or no fault coverage will ensure that you are covered by your insurance company no matter who is at fault. Uninsured or underinsured coverage makes sure that you are covered even if the other party does not have insurance or does not have enough to cover the full cost of damages to you and your vehicle.