Research On Urban Access Management

Access management is the systematic control of the location, spacing, design, and operation of driveways, median openings, interchanges, and street connections to a roadway. It also involves roadway design applications, such as median treatments and auxiliary lanes, and the appropriate spacing of traffic signals. The purpose of access management is to provide vehicular access to land development in a manner that reduces the problems of safety and efficiency attributable to unmanaged vehicular access.Based on the experiences of access management in America, this research does data collections on medians and driveways of major roadways in Beijing, and studies systemically impacts of fencing medians on left-turn, U-turn vehicles and crossing pedestrians, and do some primary researches of driveway and separators which divide vehicles and bicycles. Based on analysis, we find some problems about them, and then propose some measurements to improve in design and management. At last of this thesis, we will do some efficiency evaluation for the measurement.By managing roadway access, we can extend the life of roads and highways, increase public safety, reduce traffic congestion, and improve the appearance and quality of the built environment. Not only does access management preserve the transportation functions of roadways, it also helps preserve long-term property values and the economic viability of abutting development. From an environmental perspective, improved traffic flow translates into greater fuel efficiency and reduced vehicular emissions. Consolidating access roads is also less damaging to rural landscapes or environmentally sensitive areas than numerous individual private drives.It is worth mentioning, this study is the first time to do date collection and reduction about the impacts of fencing medians on road traffic, and analysis it systematically. During this study, we find that fencing medians provide no refuge area for pedestrians crossing the roadways at intersections, and result frequent U-turn vehicles at some intersections which increase many delays to left-turn vehicles, and even through traffic along major roads. And through this study, we hope traffic engineers engaged in planning, designing and management can be aware of the importance of access management, and the necessity of access management in urban road management for the future.