从公路隧道运营通风、行车安全、隧道施工的角度 ,论证并阐述了隧道设计纵坡与前三者的关系 ,从技术可行、经济合理、实施可能的角度 ,提出了公路隧道的最大设计纵坡可控制在 4%以内 ,特殊困难的短隧道(5 0 0 m以内 )可不受此限。 From the perspective of tunnel ventilation, traffic safety and tunnel construction, the relationship between the vertical gradient of tunnel design and the former three is demonstrated and elaborated. The maximum design longitudinal slope of highway tunnel is put forward from the view of technical feasibility, economic rationality and possible implementation. Short tunnels (up to 500m) that can be controlled within 4% and have special difficulties are not subject to this limit.