presence vehicle detector

例句：

1. 1. The presence vehicle detector is designed todetect the presence of vehicles in a givenarea.
   存在车辆探测器旨在检测指定区域内的车辆存在。
2. 2. The vehicle detector has been upgraded to improve its accuracy and reliability.
   车辆探测器已升级以提高其准确性和可靠性。
3. 3. Thepresence vehicle detector is used to monitor trafficflow and prevent accidents.
   存在车辆探测器用于监控交通流量，以防止事故的发生。