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How do the police gather evidence during traffic stops?

On Behalf of | Mar 15, 2024 | Criminal Defense

The police can stop a vehicle if they have reasonable suspicion that a driver violated traffic laws, such as drunk driving. For a driver to be lawfully arrested and face criminal charges and penalties after a traffic stop, the police need to have probable cause. To obtain this, the police gather evidence proving that there was probable cause to arrest the driver. 

There are a few ways the police can gather evidence during a traffic stop. Here’s how:

Police questioning 

The police can ask drivers questions to determine whether a driver knows why they are being stopped. A driver may be asked, for example, whether they are drunk, have been drinking alcohol or consuming substances or if they had recently left a bar. These questions can help determine whether a driver was drunk and if the police need to make any further investigations.

However, a driver may plead the Fifth. Pleading the Fifth allows a driver to refuse to answer any questions that could lead to self-incrimination, but they are also showing that they are willing to cooperate in other ways. 


The police may also look in a vehicle to see if there is any evidence that laws were broken. The police can’t search a vehicle unless they have a warrant, permission from a driver or have made a lawful arrest. But, they can look in the windows to see if there are any weapons, open bottles of alcohol or substances. 

Field and chemical sobriety tests

If the police still do not have enough evidence, they may ask drivers to do field or chemical sobriety tests. Field sobriety tests allow the police to gather visual evidence of drunkenness. Chemical sobriety tests evaluate the amount of alcohol in a driver’s body. 

If a driver is arrested without probable cause, then the police may have violated their legal rights. It can help to reach out for legal help to assess your defense options.