No driver likes to see blue-and-red lights flashing in their rearview mirror, but what should you do when a law enforcement officer signals for you to pull over? What can the officer tell you to do?

Lt. Jake Mahoney, a spokesman for the Aiken Department of Public Safety, said it's the responsibility of a driver to first signal to the officer that they know they are being stopped, then pull to the side of the road.

From there, officers would like to see a driver remain in the vehicle, keep their hands in plan view, and turn on the interior light of your vehicle if it is a nighttime stop. Also, passengers in rear seats are asked to place their hands on the seat in front of them.

“From the officer's perspective, we do not know who we're stopping on most occasions,” Mahoney said. “We don't know the offenders, so there's always risk when the officers approach a vehicle.”

Keep your driver's license, insurance and vehicle registration in close reach, but don't retrieve them until the officer asks you to.

Can an officer order you and any occupants from your vehicle at a traffic stop without an additional reason?

If an officer asks you or the occupants to step out of the vehicle, you have to comply.

“The Supreme Court has stated that, due to the inherent dangers dealing with the unknown in those types of traffic stops, that it is not unreasonable for the officer to order the driver or passengers from the vehicle,” Mahoney said.

The court ruled in Pennsylvania vs. Mimms that an officer faces an “inordinate risk” while confronting someone in an automobile, and in that case cited a study, “Police Officer Shootings – A Tactical Evaluation,” which concluded that about 30 percent of police shootings happened while an officer approached a suspect seated in a vehicle.

An officer can also order a driver to roll down their windows.

“Asking someone to roll a window down is less intrusive than asking them to exit the vehicle,” Mahoney said.

Can you be pulled over for trying to avoid a checkpoint?

If you're approaching a police checkpoint and are thinking about trying to avoid it, you might want to think again.

Mahoney said different agencies throughout the state have policies on pulling over someone trying to avoid a checkpoint.

“The catch for the offender, so to speak, is if they make a turn, which the turn itself would be illegal – a U-turn, driving left of center, driving off the shoulder of the road – that unlawful act would be probable cause for a traffic stop,” he said.

Do you have to present your driver's license?

When an officer asks for your driver's license during a traffic stop or checkpoint, you're required by law to present it.

“When you take the test and you accept that driver's license, it is a requirement that you have that with you, that it be with you when you're operating a vehicle,” Mahoney said.

Also, passengers in the vehicle are required to identify themselves, if an officer asks.

“Depending on the nature of the stop, passengers are not necessarily being detained,” Mahoney said, adding that one passenger may be a suspect in a crime such as a shoplifting. “The vehicle may contain more offenders than just the driver. The driver may not be the offender, but that's their mode of transportation, so it does depend on the circumstances.”

If you are a concealed carry permit holder, state law requires that you give the officer your permit along with your driver's license and inform them that you are armed.

Don't argue.

Most likely, you won't exactly be thrilled to get that citation the officer hands you. If you disagree with the charge or punishment, don't argue with the officer.

“It is not uncommon for folks to disagree with being charged with a violation; the side of the road is not the place to do that,” Mahoney said. “If someone has an issue with whether or not they were actually guilty of the offense, the proper place to argue that would be in court.”

Unmarked cars can pull you over, too.

If those blue lights flooding your rear and side mirrors are on an unmarked car, you still have to pull over. Aiken Public Safety, the Aiken County Sheriff's Office and the North Augusta Department of Public Safety all have unmarked cars that are “well equipped” with lights, sirens and PA systems, Mahoney said.

But what if you're unsure if it's a real officer in that unmarked car?

“The question comes up – 'What if I'm alone? I'm by myself, it's nighttime. I'm not really sure that this is a police officer,'” Mahoney said.

First, signal to the officer that you recognize their intent to stop you, he said. Then, drive to a well-lit location such as a store parking lot, a restaurant or a business that is well-occupied at night.

“We don't recommend that people drive and talk on the cellphones under normal circumstances,” Mahoney said, “but they can always call 911 and say, 'I have a police officer behind me in an unmarked vehicle attempting to pull me over on Whiskey Road. I'm a little nervous. Is that actually a police officer?'”

When can an officer search your vehicle?

A police officer can search your vehicle – if they have probable cause, which Mahoney said can be an odor of drugs or alcohol or if a K-9 alerts to the presence of contraband in the vehicle.

If you're suspected of driving under the influence, officers will administer standard field sobriety tests to determine if you are sober enough to drive.

“If they refuse those tests, it makes it harder for the officers to exclude other reasons for the poor driving,” Mahoney said. “Those field sobriety test are only a portion of what we use to determine if there's probable cause for an arrest.”

A reading from a Breathalyzer – a device that measures a person's blood-alcohol content – can only be taken after a person has been placed under arrest for DUI.

“South Carolina does not allow the use of any passive alcohol sensors or roadside alcohol devices,” Mahoney said. “Other states have them. That could be probable cause, and that can be used in court.”

If you get stopped by an officer, keep your cool.

“Obviously, there was some reason for the stop, whether it was a traffic offense or observed criminal activity. In many cases, a vehicle description may be given to an officer as a possible suspect in criminal activity,” Mahoney said. “If you are stopped, just understand that our goal is to keep the community safe. … We're not in the business of generating revenue. We are in the business of keeping the citizens safe for travel.”

Teddy Kulmala covers the crime beat for the Aiken Standard and has been with the newspaper since August 2012.

He is a native of Williston and majored in communication studies at Clemson University.