What can be used as probable cause for a traffic stop?

What can be used as probable cause for a traffic stop?

On Behalf of | Sep 12, 2022 | DUI

Many DUI arrests simply start as a traffic stop. There are certainly cases in which the police believe someone is intoxicated in advance. But a lot of these stops happen when the police don’t know why the driver made a mistake, but they simply want to pull them over for that mistake and find out more. This is when an officer may realize that the driver is impaired and make an arrest.

However, it is unlawful for the police to make random stops of any cars that they want simply to see if these drivers are intoxicated. To conduct a legal traffic stop, they need to have some sort of probable cause in advance. There must be reasonable suspicion that the stop is warranted. So what types of things will they look for?

Standard traffic driving errors

To start with, police are going to look for normal mistakes that drivers make routinely. These include things like breaking the speed limit or changing lanes without signaling. An officer who pulls someone over on these grounds may not have any suspicion at all that the person is intoxicated. These mistakes are common enough that many sober drivers still make them.

Signs of impairment

Officers will also analyze the way that someone is driving to look for any potential signs that they are impaired. Some examples include:

  • Weaving within the lane
  • Driving right on top of the centerline
  • Making extra-wide turns
  • Driving below the speed limit
  • Failing to start moving when a light turns green
  • Stopping much to far before a red light
  • Running a red light or a stop sign
  • Drifting off the side of the road
  • Being involved in a near miss situation with another vehicle


These are just a few examples, but they help to show you the types of things that police are looking for. Perhaps more importantly, they also demonstrate that police need to have a reason for the traffic stop to initially occur, long before any sort of drunk driving arrest takes place. If you believe the police have made an unlawful arrest or violated your rights, then you absolutely need to know about your criminal defense options.