Speed is the most critical factor of road safety

higher speed and speed changes increase the number of accidents and the probability of casualties. There is an urgent need in China to develop a relatively clear speed management framework and system speed management measures. Through the empirical study of the relationship between speed and accident

it is found that higher speed limit road is more likely to cause higher mortality rates

and speed shifting areas including accesses of expressway and other urban roads are inclined to cause accidents and serious consequences. Taking the speed management methods in developed countries as reference

speed management framework was proposed in Shenzhen

including two aspects

namely safer speed and safer speed change

the key measures under this framework mainly contains speed limit adjustment of road segements

expressway speed management and access speed management

which can effectively improve the level of road traffic safety.