When Can the Police Pull Me Over?

Many criminal cases arise out of police contacts that occur on the roadway. A driver may be stopped for a minor traffic infraction, and before she knows it, what should have been a simple traffic ticket results in a physical arrest.

I’ve had many clients ask me to explain to them how this can happen. 

Lawful traffic stops must be supported by reasonable suspicion. Reasonable suspicion is a legal term used to describe a level of information that the officer must be able to describe as justification for stopping a vehicle. It is a low threshold. Reasonable suspicion can be any traffic violation. For an example, think about simple violations like forgetting to use a turn signal, or having a burnt-out headlight. 

That’s it. A simple violation is all the police need to stop a vehicle. Once the vehicle is stopped, the analysis gets more complicated. Because the driver has committed a traffic violation, the police are authorized to approach the vehicle and identify the driver to facilitate their investigation and potentially issue a citation. But what happens when the police officer walks up to the driver’s window and smells marijuana or sees an open bottle of alcohol?

Additional information observed by police officers investigating the initial purpose of the stop is supplemental, and is used to legitimize what is referred to as the “expansion of the stop.” What started as a simple traffic stop, can become a full-blown criminal investigation based only on a few sensory observations by a police officer. Once those observations are made, the officer may have reasonable suspicion that a new crime is occurring, giving the officer authority to investigate new, more serious crimes.

Here is a common scenario: A police officer pulls over a speeding vehicle. The officer approaches the driver. The officer notes the odor of alcohol coming from inside the vehicle. The officer looks at the driver. The officer says the driver’s eyes are bloodshot and glassy. The officer speaks to the driver. The officer says the driver’s speech is slurred. In this example, assuming there was reasonable suspicion to stop the vehicle for the speeding violation, when the officer approached the driver and made additional observations, she likely established reasonable suspicion of DWI, and will in turn expand the purpose of the investigation. 

It’s important to know that reasonable suspicion does not mean the officer has probable cause. Probable cause is required for a police officer to make a lawful arrest, whereas reasonable suspicion merely gives officers authority to detain a driver and investigate further. 

Understanding the progression of a criminal investigation and the governing legal standards is a critical part of any criminal defense strategy. My experience as a police officer, prosecutor, and defense attorney helps my clients both protect their rights, and understand their risks in navigating the criminal justice system. I encourage anyone who is charged, or is worried they might be charged, with a crime to contact a reputable and experienced criminal defense attorney.