You are impaired when your ability to operate a vehicle is affected by alcohol, drugs, or other substances that reduce coordination and reaction time. Impaired driving is a leading cause of fatal car accidents, often resulting in catastrophic injuries and life-changing consequences. Recognizing the signs of impairment and making responsible choices can prevent devastating crashes and keep roads safer.
Legal Definition of Impairment in California
Impairment occurs when your ability to drive safely is affected by alcohol, drugs, fatigue, or any other factor that reduces reaction time and diminishes judgment. Law enforcement determines impairment using physical observations, field sobriety tests, and chemical tests like breathalyzers or blood analysis. California law defines impairment and establishes penalties for driving under the influence through these key statutes:
- California Vehicle Code § 23152 – Prohibits driving under the influence of alcohol or drugs, setting the blood alcohol concentration (BAC) limit at 0.08% for most drivers and 0.04% for commercial drivers.
- California Vehicle Code § 23153 – Establishes increased penalties if a driver causes an accident while under the influence, leading to injury or death.
- California Vehicle Code § 23612 – Enforces implied consent laws, requiring drivers who are lawfully arrested for DUI to submit to chemical testing. Refusing a post-arrest test can result in automatic license suspension, but drivers over 21 who are not on DUI probation may legally decline a preliminary breath test before arrest.
Law enforcement officers use breathalyzers, blood tests, and behavioral assessments to determine impairment. If you fail a sobriety test or refuse chemical testing, you could face immediate penalties, including license suspension. Violating DUI laws can also make you financially responsible for any damages or injuries caused by your impaired driving.
Factors That Can Impair Your Ability to Drive
Impairment is not limited to alcohol use. It includes anything that affects your ability to focus, react, and control your vehicle. You may not realize how certain substances, exhaustion, or distractions impact your driving until it is too late. Recognizing these risks can help you make safer choices before getting behind the wheel.
Alcohol and Drug Impairment Behind the Wheel
Even small amounts of alcohol or drugs can affect your ability to drive safely. Alcohol reduces coordination, slows reaction time, and impairs judgment, increasing the likelihood of making dangerous decisions. Many drivers assume they are fine after just a couple of drinks, but even a BAC below 0.08% can still impair driving ability.
Drug impairment is just as dangerous, whether from illegal substances or legally prescribed medications. Marijuana use, for example, can slow reaction time and distort perception, making it harder to judge distances. Stimulants, opioids, and sedatives all affect motor skills differently, but any drug that alters cognitive function increases the risk of a crash.
Fatigue and Drowsy Driving’s Impact on Reaction Time
Driving while exhausted can be just as dangerous as driving under the influence of alcohol. Fatigue slows reaction time, reduces awareness, and increases the likelihood of falling asleep at the wheel. Studies show that going 20 hours without sleep has the same impact on driving ability as having a BAC of 0.08%.
Drowsy drivers often struggle to keep their eyes open, maintain a steady speed, or react to sudden changes in traffic. Long-distance driving, overnight shifts, or untreated sleep disorders can all contribute to this risk. If you feel yourself struggling to stay awake, it is safer to pull over and rest rather than risk causing an accident.
Distractions That Can Mimic Impairment While Driving
Distracted driving impairs your ability to react just as much as alcohol or drug use. Texting, adjusting the radio, or even talking to passengers can take your eyes off the road long enough to miss critical hazards. When you are not fully focused, you are more likely to drift between lanes, run red lights, or brake too late to avoid a crash.
Using a phone while driving is particularly dangerous because it affects your visual, manual, and cognitive abilities at the same time. Sending or reading a text takes your eyes off the road for an average of five seconds…enough time to cover the length of a football field at highway speeds. If your attention is not on the road, you are not in full control of your vehicle.
Recognizing the Signs of Driver Impairment
Impaired drivers pose a serious threat to everyone on the road. Whether they are under the influence of alcohol, fatigued, or distracted, their behavior is often unpredictable. Learning to recognize the warning signs of impairment can help you avoid dangerous drivers and report them before they cause a crash. Some of the signs of impairment that increase crash risk include:
- Weaving between lanes and erratic steering – Drifting from side to side or overcorrecting can indicate a lack of control.
- Sudden or delayed braking without reason – Impaired drivers may react too late or slam on the brakes unnecessarily.
- Driving at inconsistent speeds or too slowly – Failing to maintain a steady speed can be a sign of impaired judgment.
- Ignoring traffic signals or road signs – Running red lights or failing to yield suggests reduced awareness.
- Falling asleep or appearing dazed while driving – Drowsy or drug-impaired drivers may struggle to stay awake behind the wheel.
- Using the wrong lane or turning improperly at intersections – Confusion about traffic rules or poor coordination can indicate impairment.
If you notice these signs in another driver, increase your distance and avoid passing them unless absolutely necessary. Reporting an impaired driver to law enforcement could prevent a serious accident and save lives.
The Consequences of Driving While Impaired
Driving while impaired puts you, your passengers, and others on the road in serious danger. Alcohol, drugs, fatigue, and distractions all reduce reaction time, affect judgment, and increase the risk of accidents. If you get behind the wheel while impaired, you could face legal penalties, financial liability, and long-term consequences on your driving record.
Legal Penalties for Driving Under the Influence
If you are caught driving while impaired, you could face serious legal consequences. California law imposes harsh penalties for DUI offenses, even for first-time offenders. Fines, mandatory alcohol education programs, and potential jail time are all possible outcomes of a DUI conviction.
For repeat offenders or those involved in accidents, the penalties are even more severe. If you cause a crash while under the influence, you could be charged with a felony DUI, leading to years in prison. Your criminal record will also reflect the conviction, which can impact employment opportunities and insurance rates.
Note
In California, refusing a breathalyzer test after being lawfully arrested for DUI can result in an automatic license suspension under the implied consent law. This penalty applies even if you are later found not guilty of DUI, making refusal a risky decision.
Insurance and Civil Liability in Impaired Driving Cases
A DUI conviction can make it harder for you to get car insurance. Many insurance companies consider impaired drivers to be high-risk and may increase premiums significantly. In some cases, a DUI could result in your policy renewal being denied.
If you cause an accident while impaired, you may also be financially responsible for any injuries or damages. Victims of DUI-related crashes can file lawsuits against the at-fault driver to recover medical expenses, lost wages, and pain and suffering. In cases of extreme negligence, courts may award punitive damages, which can lead to even greater financial loss.
Impact on Driving Privileges and License Suspensions
California law allows for immediate license suspension if you are arrested for DUI. If you refuse a breathalyzer or fail a sobriety test, your license can be suspended even before a conviction. The length of the suspension depends on prior offenses and the severity of the case.
In some cases, drivers may be required to install an ignition interlock device (IID) to regain limited driving privileges. This device prevents the vehicle from starting unless the driver passes a breathalyzer test. Repeat DUI offenders may face permanent license revocation, making it impossible to legally drive.
Field Sobriety and Chemical Testing for Impairment
Police officers use a variety of tests to determine whether a driver is impaired. If you are stopped under suspicion of DUI, you may be asked to complete a field sobriety test or submit to chemical testing. Failing or refusing these tests can result in immediate legal consequences. Law enforcement determines driver impairment through:
- Standardized field sobriety tests, including the walk-and-turn test – Officers observe balance, coordination, and the ability to follow instructions.
- Breathalyzer tests to measure blood alcohol concentration (BAC) – A BAC reading above 0.08% is considered legally impaired for most drivers.
- Blood and urine tests for drug and alcohol levels – These tests detect substances that may not show up on a breathalyzer, such as marijuana or prescription drugs.
- Officer observations of speech, coordination, and behavior – Slurred speech, delayed reactions, and confusion are common signs of impairment.
Test results are often used as primary evidence in DUI cases. If a breathalyzer or blood test confirms impairment, it can be difficult to fight the charges. However, law enforcement officers must follow strict procedures when administering these tests, and any mistakes in protocol can be challenged in court.
Tip
If you are pulled over for suspected DUI, remain calm and avoid making statements that could be used against you. You are required to provide your license, registration, and insurance, but you do not have to answer questions about whether you have been drinking. Politely declining to answer can prevent self-incrimination.
Defenses Against Allegations of Impaired Driving
A DUI charge does not always mean an automatic conviction. In some cases, evidence can be challenged, or other factors may explain why a driver appeared impaired. Knowing your legal options can help you fight unfair charges.
Challenging Field Sobriety Test Accuracy
Field sobriety tests are not always reliable. Many factors, such as medical conditions, uneven road surfaces, or poor lighting, can cause a sober driver to fail these tests. Officers who do not properly administer the test or misinterpret the results may incorrectly determine that a driver is impaired.
If you were arrested based on a failed field sobriety test, an experienced attorney can challenge the validity of the results. Video footage from the officer’s body camera or dashcam may also provide evidence that the test was unfair or improperly conducted.
Medical Conditions That Can Mimic Impairment
Certain medical conditions can cause symptoms that resemble impairment. Diabetes, neurological disorders, and even severe allergies can lead to slurred speech, dizziness, or poor coordination. Some individuals may also have difficulty performing field sobriety tests due to physical limitations.
If you were arrested for DUI due to a medical condition, providing medical records and expert testimony can help prove that your symptoms were unrelated to alcohol or drug use. In some cases, prescription medications can also cause impairment-like side effects, which should be considered in a defense strategy.
Errors in Breathalyzer and Blood Testing
Breathalyzer machines must be properly calibrated and maintained to provide accurate readings. If an officer used a faulty device or failed to follow proper procedures, the results may not be admissible in court. Similarly, blood samples must be handled correctly to avoid contamination or inaccurate readings.
A skilled attorney can request maintenance records for the breathalyzer machine used in your case. If errors are found, the test results may be thrown out, weakening the prosecution’s case against you.
Pro Tip
If you are involved in an accident with an impaired driver, document everything at the scene. Take photos of vehicle damage, injuries, road conditions, and any visible signs of impairment in the other driver. If there are witnesses, get their contact information. This evidence can strengthen your injury claim.
Find Out How We Can Help After a Drunk Driving Accident
Drunk or drug-impaired drivers put lives at risk, often causing severe or fatal accidents. Your car accident attorney from Crockett Law Group will fight to hold negligent drivers accountable and secure the financial recovery you deserve. Contact a car accident lawyer at our firm today to take legal action and protect your rights.
