Definition
to signal a driver to stop a vehicle by gesturing with your arms.
揮手攔下（車輛）
She waved the driver down to stop.
她揮手讓司機停下來。
He waved down a taxi from the side of the road.
他在路邊揮手攔下了一輛計程車。
The police officer waved the speeding car down.
警察揮手讓超速的汽車停下。