Understanding Probable Cause in DUI Cases

Legally reviewed by:
Rubin, Glickman, Steinberg & Gifford P.C.
February 19, 2021

If a police officer suspects that you’re driving over Pennsylvania’s legal BAC limit—0.08 percent—they have the right to detain you for questioning, search for evidence, and make a DUI arrest. However, to do so lawfully, they must first establish probable cause. The United States Constitution states that law enforcement must have a certain level of justification before they initiate a traffic stop and subsequent DUI arrest. When these standards aren’t met, you may have legal recourse.

If you’ve been arrested for driving under the influence in Pennsylvania, it’s important that you understand probable cause to determine whether your rights have been infringed upon. We’ve broken down everything you need to know about establishing probable cause in Pennsylvania.

What Does Reasonable Suspicion and Probable Cause Mean in the Context of a DUI Stop?

Before you understand probable cause, it’s important to understand the concept of “reasonable suspicion.” A police officer can detain a person for questioning, search for evidence, and make a DUI arrest in Pennsylvania if they establish both reasonable suspicion and probable cause. Although these two terms are sometimes used interchangeably, there are several key differences.

Reasonable Suspicion in DUI Cases

In Pennsylvania, law enforcement must have a reasonable suspicion that a person has violated the law in order to lawfully pull them over for driving under the influence. This means that an officer has reason to believe—based on their training and experience—that a crime has been committed, is being committed, or will be committed.

While reasonable suspicion is subjective in nature, law enforcement officials must have more than a hunch or gut feeling to detain someone. Certain facts and circumstances must be apparent. For example, if an officer notices that a driver commits a traffic violation or is otherwise driving erratically, the officer has reasonable suspicion that the driver is intoxicated and can pull them over.

Probable Cause in DUI Cases

While reasonable suspicion allows an officer to temporarily stop and detain a motorist, an officer must meet a higher standard of “probable cause” before obtaining a warrant, searching a vehicle, or arresting a suspected drunk driver. In general, probable cause requires facts that demonstrate a high probability that the driver is impaired or consumed alcohol in excess of the legal limit. Visual findings, like a driver’s mannerisms, speech, or behavior, can be enough to meet probable cause standards. A police officer may also establish probable cause by other means, including the smell of alcohol or open containers in the car.

The main difference between reasonable suspicion and probable cause is that the former exists if a reasonable officer suspects criminal activity, while the latter exists if it can be assumed that a reasonable individual who’s not a police officer would suspect a crime based on the actions of the suspect.

One common tool that Pennsylvania law enforcement uses to establish probable cause is a breathalyzer. These devices are used to estimate blood alcohol content (BAC) from a breath sample. Another go-to technique that police often utilize to establish probable cause after a DUI stop are field sobriety tests. This brief examination typically involves a one-leg stand, horizontal gaze nystagmus, and a walk-and-turn in Pennsylvania.

It’s important to note that if the police fail to identify facts that lead to probable cause, any evidence gathered from that point on may not be admissible in court. This may lead to a dismissal in some cases. If you think this may be the case, it’s vital that you get in touch with an expert Montgomery County DUI defense lawyer who may be able to help you reduce or eliminate the penalties associated with a conviction.

Contact an Experienced DUI Defense Lawyer in Montgomery County

If you were charged with a DUI and think that an officer might not have met probable cause or reasonable suspicion requirements, we invite you to contact us for a free consultation. At Rubin, Glickman, Steinberg & Gifford we understand how challenging this time can be for you, which is why we’re dedicated to fighting for your rights and protecting your interests throughout the legal process. Our highly trusted and well-versed legal team understands the ins and outs of Montgomery County DUI defense law and will be with you every step of the way.

For more than 65 years, the attorneys at Rubin, Glickman, Steinberg & Gifford have been serving the legal needs of clients in Montgomery County, Bucks County, Lehigh County, Chester County, Delaware County, and throughout the surrounding areas. We’ve earned the trust and respect of clients facing a wide range of legal problems. Our attorneys are ready to protect you and guard your rights. Call (215) 822-7575 or complete our online contact form today.

Legally reviewed by:
Rubin, Glickman, Steinberg & Gifford P.C.
Pennsylvania Attorney's
February 19, 2021
Established in 1952 by Irwin S. Rubin, Rubin, Glickman, Steinberg & Gifford P.C. boasts over 65 years of experience serving clients throughout Pennsylvania. Renowned for its commitment to ethical representation, the firm has garnered prestigious accolades, including being named the "Best Law Firm" for its outstanding legal defense work by U.S. News & World Report. Their team of seasoned attorneys, recognized as Pennsylvania Super Lawyers and Rising Stars, brings unparalleled expertise to a wide range of legal matters, ensuring exceptional representation for individuals, families, businesses, and organizations.