add parseInt() to ensure the type of busData.route_dir

              closestSegment[0][1], closestSegment[0][0],

              closestSegment[1][1], closestSegment[1][0]

          );

          busHeadingAngle = busData.route_dir === 1 ? busHeadingAngle : busHeadingAngle - 180;

          busHeadingAngle = parseInt(busData.route_dir) === 1 ? busHeadingAngle : busHeadingAngle - 180;

          // 创建标记元素

          const busMarker = document.createElement('div');

    createPopup(busData) {

      let routeDirText;

      const routeCodeLastDigit = busData.route_code.slice(-1);

      const routeCodeLastDigit = busData.route_code.slice(-1); // 检查是XYBS1还是XYBS2

      if (routeCodeLastDigit === '1') {

        routeDirText = busData.route_dir === 0 ? '欣园 Joy Highland' : '工学院 COE';

        //log car plate and route dir

        // console.log("Car plate: " + busData.id.slice(2,) + " Route dir: " + busData.route_dir);

        routeDirText = parseInt(busData.route_dir) === 0 ? 'RD0 欣园 Joy Highland' : 'RD1 工学院 COE';

      } else if (routeCodeLastDigit === '2') {

        routeDirText = busData.route_dir === 0 ? '欣园 Joy Highland' : '科研楼 Research BLDG.';

        routeDirText = parseInt(busData.route_dir) === 0 ? 'RD0 欣园 Joy Highland' : 'RD1 科研楼 Research BLDG.';

      } else {

        routeDirText = '未知'; // Fallback text in case neither condition is true

      }