Based on the analysis of urban road traffic flow affected by emergency vehicle, a muti-lane cellular automaton model is established. Three characteristic variables are introduced to modify the lane change rules, including the give-way state variable, the affected areas of police siren and the safe distance for mandatory lane change. Numerical simulation results indicate that lane number and hybrid vehicle scale factor have a great influence on vehicle speed and lane change number in low-density range. And the parameter setting for affected areas of police siren changes the lane change number within a certain range. Meanwhile, the parameter of safe distance for mandatory lane change mainly affects emergency vehicle speed and lane change number. The study indicates that the appearance of emergency vehicle interferences with traffic flow of lower density obviously, and the proposed parameters make cellular automaton model closer to the actual traffic scenarios under emergency conditions.

To improve the traffic safety at the two-phase intersection, collision risk value between the left-turn vehicle and the straight vehicle in the opposite direction could be used to judge their order. Based on the safety and risk, this method analyzed the process of conflict, modified the operating parameters and then collision risk analysis model was proposed. In the paper, one practical example was given. The result shows that the method can be applied to design the signal phasing-sequence of traffic at signalized intersection, which not only improve safety theory but also provide the theoretical basis for security information service.