Study on the Mountainous Freeway Vertical Alignment Safety Based on Typical Truck Climbing Characteristics in China

Four most popular trucks in China are chosen, the engine performances of which were analyzed by bench test. The truck's climbing ability was calculated based on dynamics principle, and the result show that the current vertical alignment indexes cannot guarantee the trucks to travel at minimum freeway speed limit 60km/h. Based on the truck's climbing ability, the equilibrium climbing speeds at different grades are calculated, and the maximum grade length limitation at different grades is also recommend when design speed is 80km/h, critical speed is 60km/h.