Reasonably organizing the left-turn flow at the at-grade intersection can directly impact the driving safety and road capacity.Left-turn prohibition is an important approach to organizing the surface intersection,and its effects are relevant to many factors.Based on the characteristics of the left-turn traffic flow,this paper analyzes the mechanism of intersection delay change after the left-turn is prohibited.Through reorganization of the traffic flow while left-turn is prohibited,a computing model for intersection delay change is developed.Through the modeling analysis,it finds out some important boundary conditions including intersection saturation,network density and left-turn ratio.Meanwhile the paper analyzes the way these boundary conditions impact on the left-turn prohibition effects.

Car-sharing, as an advantageous travel mode, has rapidly developed in Europe and North America.Firstly, this paper explains the basic definition of car-sharing, then introduces the development of car-sharing in north America, including the number of organization, total membership and vehicle trends, member-vehicle ratios, business models, current and future market developments, existing and future demographic markets and Rate Structures.