The new conference was held on Interstate 99 and police pulled over drivers during the event.

Under Pennsylvania law, if an emergency vehicle has pulled another vehicle off to the side of the road, other drivers must move to the passing lane. If a driver can't safely change lanes, he or she must slow down.

The law applies not only for police, but also for any emergency vehicle and where road crews have signs and flares. The law is to make sure authorities working on the side of the road are safe.

Those caught violating the law can face a find of up to $110. If the offense happens in a construction zone, the fine is doubled.

Police also said drivers should not assume they won't be caught. On some days, like Monday, an officer will pull someone over for speeding and there will be a second officer parked nearby to make sure drivers steer clear.