Is “Sudden Stop” a defense in a rear-end collision case?

The sudden stop defense can be used by the driver of the trailing vehicle in a rear-end car accident. While generally, the driver of the trailing vehicle is liable in these accidents, that is not always the case. If the leading driver suddenly stops, in certain circumstances they may be responsible or at least share some fault for the crash.

If the leading driver makes a sudden stop, can they be liable for a car accident?

In a rear-end collision, the front of the trailing vehicle crashes into the back of the leading vehicle. In some limited circumstances, the driver of the leading vehicle can be liable, or at least partially liable, for the accident for stopping suddenly in an unsafe manner. This is known as the sudden stop defense.

Some states have traffic laws such as California Vehicle Code 22109 CVC, which forbids drivers from coming to an abrupt stop without adequately signaling to drivers immediately behind them.¹

The sudden stop defense is raised by the driver of the trailing vehicle. It is generally a part of a personal injury lawsuit in which the driver of the leading vehicle claims that the trailing vehicle caused the crash. The driver of the trailing vehicle then makes a counterclaim that it was the leading vehicle that caused it by not taking reasonable care for other drivers when they hit the brakes.

The sudden stop defense can be a strong one if the leading driver:

• did not have working brake lights,
• slammed on the brakes in a fit of road rage,
• was drunk driving or driving under the influence of drugs, or
• intentionally hit the brakes to try to cause an accident in an instance of insurance fraud.

Even in these cases, though, the trailing driver may still be held partially liable for following too closely.

Why is the trailing driver normally liable?

In a rear-end car accident, the trailing driver is typically the one who is held liable. This is because every state has a traffic law that forbids drivers from following other vehicles too closely.

In California, this law is California Vehicle Code 21703 CVC. This law imposes a duty of care on drivers to maintain a safe following distance. A rear-end collision is strong evidence that you were following the vehicle in front of you too closely and not providing a safe following distance.

There is no specific measurement that amounts to a safe following distance. Instead, the distance between the front of your car and the back of the one in front of you has to be what a reasonable person would maintain in similar circumstances. Some factors that can influence what is a reasonably safe following distance are:

• wet road conditions,
• the weight and stopping distance of the leading vehicle (smaller and lighter vehicles, like motorcycles, can stop more quickly than heavier ones),
• the weight and stopping distance of the trailing vehicle (large trucks take longer to stop),
• visibility,
• if there was heavy traffic on the road,
• whether there are roadside hazards or distractions, like children playing in a residential area, that could foreseeably require a sudden stop, and
• whether it is daytime or nighttime.

These factors can change the length of a safe following distance. Not maintaining a safe following distance violates traffic law. Because this particular traffic law is designed to protect leading vehicles from rear-end collisions, if the trailing driver breaks it, it can amount to negligence per se. The fact that the accident occurred while the trailing driver was in violation of the law makes them presumptively liable.

How does shared fault work in a personal injury claim?

Many car accidents, including rear-end collisions, are not solely the fault of one driver. Many are shared fault accidents. Both the trailing and the lead driver bear some responsibility. Different states use different rules for apportioning liability in these accidents. These rules fall into 3 categories:

1. contributory negligence,
2. pure comparative negligence, and
3. modified comparative negligence.

Only a few states, like Virginia,² still use contributory negligence. In these states, if you contribute at all to the accident then you cannot recover any compensation for your injuries. This often dooms a personal injury case filed by the driver of the trailing vehicle against the leading driver under the sudden stop defense.

Lots of states, including Florida and California,³ use pure comparative negligence. In these states, the jury in your personal injury trial has to assign a percentage of responsibility to each party involved. Your compensation is then reduced by your share of fault. For motorists in trailing vehicles that are involved in rear-end accidents, pure comparative negligence is the most friendly shared fault rule.

Some states, like Texas,⁴ use modified comparative negligence. Just like with the pure version of this rule, the jury assigns a percentage of responsibility and your compensation is reduced by your share of fault. However, unlike in pure comparative negligence states, you are barred from recovering any compensation if you were more than half at fault for the crash.

The best way to show that you were not at fault, or that your share of fault was only a small one, is to establish an attorney-client relationship with a personal injury attorney from a reputable law firm.

How is this different from the sudden emergency doctrine?

The sudden stop defense is different from the sudden emergency doctrine.

The sudden emergency doctrine holds that negligence will not lead to liability for an accident if the negligent action arose from an emergency situation.

In California, for example, you have to prove the following to raise the sudden emergency defense:

1. there was a sudden and unexpected emergency situation that put someone in either actual or apparent danger of immediate injury,
2. the person raising the sudden emergency defense did not cause the emergency, and
3. the person raising the defense acted as a reasonably careful person would have acted in similar circumstances, even if hindsight now shows that a different course of action would have been safer.⁵

In the context of a rear-end collision, the sudden emergency defense could be raised by the driver of the leading vehicle, not the trailing one. The sudden emergency defense would challenge the allegation that the leading driver was responsible for the crash. This makes the sudden emergency doctrine a rebuttal to the sudden stop defense. It would argue that, if the leading driver did stop too suddenly, it was only because of a sudden emergency.

For example: Loretta is driving safely down the road. Terry is behind her at what he thinks is a safe distance. A child darts into the road in front of Loretta. Loretta slams on the brakes and stops suddenly. Terry is unable to stop in time and crashes into Loretta. Loretta sues Terry for the motor vehicle accident. Terry raises the sudden stop defense, claiming that Loretta should be liable because she stopped unreasonably. Loretta raises the sudden emergency defense, arguing that she had to stop quickly to save the child.

These accident cases can be complex. An experienced personal injury lawyer can help victims or other passengers in the plaintiff’s vehicle recover compensation from the defendant driver’s insurance company.