Concept Design and Evaluation of Traffic Management in Beijing

Abstract

With the pace of economy and the level of urbanization speedup, the vehicle possessions and usage has increased. The resulting traffic congestion has become a big problem in modern cities. Instead of new infrastructure supply, attention has been switched to a more efficient use of existing infrastructure. The fact that current road network capacity has not fully explored offers the opportunity for traffic management to play a role. Commissioned by the Dutch Ministry of Transport, Public Works and Water Management, a pilot project called Praktijkproef Verkeersmanagement Amsterdam (PPA) as one of the most ambitious traffic management projects has finished its concept proof and ex-ante evaluation phase. In the project, a hieratical multi-level control approach is proposed for the metropolis of Amsterdam with various measures from local upgrades to network integrated traffic management. It is recognized that as more and more DTM measures are deployed, integration is needed to play full effect. Encouraging initial results have enlightened for investigation in other countries. Beijing, the capital of China, witnesses the boost economic and urban development in the past decades. At the same time, it is challenged by unprecedented traffic problems. In this study, the concept inspired by PPA project is extended to Beijing. Given the different background, the objective of the research is to investigate traffic characteristics in Beijing, conceptually design traffic management measures and schemes specific to Beijing situation, predict and evaluate the potential of traffic management in improving the traffic in Beijing. The need for traffic management can be explicated both from theoretical and policy perspective. From traffic theory, either conventional fundamental diagram or macroscopic fundamental diagram reveals the traffic property on link and network level. The underlying mechanisms indicate opportunity for the design of effective traffic management measures. And among the policy instruments, utilization weights out to be the optimal. Literature and past experience in traffic management are reviewed then on. Subsequently, the research objective is achieved by exploring to the Beijing network. Beijing has generally a distinguished grid type network with six urban ring expressways as the skeleton. Due to the recourse limitation in urban area, further road expansion is difficult. While at the same time, the considerable expansion rate of car-owner ship is expected to remain. In this case, it is anticipated that the gap between supply and demand will further grow. Next to that, the study digs into details of the network, figuring out the unique road structure and corresponding traffic flow behaviour. It is found that the urban ring expressway is very different from regular highway in structure, and so is the traffic composition on expressway. Lack of interface between expressway and urban roads as one of distinct points receives attention. The sensitive areas in the proximity of the interface: virtual on-ramp, off-ramp and weaving area is focused. Besides, other general traffic characteristics on main roads and distribution on different grade of roads are studied. Based on the findings, some traffic measures are innovated in the study tailoring to the traffic characteristics in Beijing. On a local level, static measures as simple infrastructure adjustment are recommended in accordance with local situation, and dynamic measures are further proposed in an attempt to be better reactive to the prevailing traffic dynamics. Afterwards, a four-phase integration framework is designed specific for incident situation as the first trail approach of traffic management integration. In the ensuing of this study, a case study is performed on a sub-network area in Beijing to predict and evaluate the potential of the proposed measures. It is done with the approach of simulation and modelling, DYNASMART-P 1.4 is utilized as the main simulation tool. According to the simulation result, local measures do show effect on local level, but deteriorate the network performance. As far as the author is considered, since the difference is so minor, some influential factors should be reconsidered. Under the two-designed incident case, integration of DTM measures according to the proposed phase scheme shows obvious effect in ameliorating the influence of non-recurrent case. However, the optimal phase of integration differs according to the severance of incident, indicating the decision point of level of integration is of an important issue. With the experience from foreign countries, research investigation, and modelling results, the future of Beijing traffic management is prospected at the end. Requirements of different phases of the traffic management development are looked into for Beijing case, it is concluded that traffic management is of potential and opportunity, thus should be paid special attention to in the future development in associating with other necessary policy instruments.