The restriction may be temporary due to bridge or other construction works 有时候，由于桥梁或其他建筑工程的影响，会有暂时的通行高度限制。
2.
A warning sign will indicate the maximum headroom and that part of the road where the indicated headroom is available 警告标志会说明最大的通行高度，以及在道路哪一处，会有通行高度限制。
3.
Advanced warning of restricted headroom may be given by a restricted headroom ahead warning sign with a supplementary plate showing the distance to the restriction 前面有通行高度限制的警告标志，用以预先警告驾驶人，并有辅助标志牌，说明限制生效的地点距离有多远。
