沿主要幹線每隔一段距離設置的標誌，顯示駕駛人在幹線上的位置。
A marker installed at regular intervals along a strategic route to show a driver's position on it.
沿主要幹線每隔一段距離設置的標誌，顯示駕駛人在幹線上的位置。
A marker installed at regular intervals along a strategic route to show a driver's position on it.