In order to charge someone for a crime, police officers need to conduct arrests lawfully. In the case of traffic violations, the police officer must also carry out the traffic stop appropriately.

Here’s when and how law enforcement can lawfully request that you pull over while driving by using their lights and/or siren.

Breaking traffic laws

Perhaps the most obvious circumstance that constitutes a traffic stop is when a driver has broken a traffic law, such as disobeying a traffic sign, exceeding the speed limit or littering.

If you admit to knowingly breaking the law, the police officer is required to penalize you, most commonly with a traffic violation ticket and fine.

Suspicious driving

It’s important to know that you may be pulled over without having broken a traffic law. However, your conduct while driving must have reasonably caused the officer to suspect that you may be violating the law.

Examples could include if the driver is drifting from side to side within a lane or the appearance of the vehicle matches a crime report.

Most commonly, drivers are pulled over in these situations when the officer suspects that the driver may be under the influence of an impairing substance. Note that an officer cannot legally pull over a driver for leaving a bar as a reason for suspicion. The conduct of the driver on the road must be the source of the officer’s suspicions.

Sobriety checkpoints

Sobriety checkpoints are predetermined areas where police may block off traffic to randomly choose test the blood alcohol level of drivers. At a sobriety checkpoint, an officer is not required to have reasonable suspicion that a driver is committing a crime in order to pull him or her over and request a breath test. Refusing a breath test from a police officer results in automatic revocation of your driver’s license for one year.

Some politicians believe this violates a citizen’s rights from random search and seizure. However, in New York, the state found that protecting public safety outweighed this concern. Additionally, these checkpoints can be avoided since their location must be somehow publicized to the general public in advance.

A complaint

Police officers can make a traffic stop if another person has called in and accused the driving of committing a crime or reported suspicious behavior. However, if a police officer was not present for a traffic violation, there’s not a high likelihood that they can press charges without proof of the incident. In these situations, it’s important not to admit fault and ask to speak to an attorney.