CHENGDU -- Two drones are being used to help monitor traffic flow and violators on highways in Southwest China's Sichuan province, according to the provincial public security department Sunday.

The drones, which can travel up to 100 km per hour, were first used, which is usually when roads are crowded with returning travelers.

The drones flew over two highways, one connecting the cities of Chengdu and Zigong, and the other connecting Chengdu with Mianyang. More than 90 traffic incidents were caught on camera by the drones.

The drones can recognize license plates from 100 meters away. The pictures and videos are sent back to ground staff, so the police can take efficient measures to direct traffic flow.

With a flight radius of 15 km, the drones can fly for up to one hour at a time, and can complete a 30 km round trip in 40 minutes.

The drones' activity was broadcasted live through the provincial traffic police's official Weibo account.

The traffic police will now use drones more regularly.