Estimating And Pricing Transport Emissions On Urban Road Networks

Urban road transport emissions have become a dominant factor damaging environmental sustainability since the 1990s, as well as jeopardizing citizens'health. Nowadays, it has emerged to be a non-negligible factor in transportation planning and management. Mathemat-ical models incorporating environmental factors were proposed in this paper to estimate urban road transport emissions. Meanwhile, in order to reduce emissions and improve transportation environment, transport emissions pricing was also investigated.Three types of estimating and pricing models were proposed and discussed. The similar-ity among them is that they all were based on static traffic assignment whereas the difference was the scope of their respective applications. First, the macroscopic road network estimating models in the literature were analyzed, on the basis of which pricing scheme was extended to transport emissions. Then, a bi-level regional emission evaluation model considering envi-ronmental tolerance was formulated and a pollution index was defined and is the output of this bi-level model. Thirdly, to make it more practical, a new type of emission estimating bi-level model combined with environmental sustainability and pricing was formulated. Compared to the former two methods, the third one interpreted emission estimating and pric-ing as a whole, treated pricing as a set of decision variables and took into account its influence on the resulting traffic flow on each link. In the numerical examples all the three methods es-timated transport emissions effectively and produced least public-burden pricing schemes.This research shows that the optimal transport emission price is closely related to the as-sumption on travel choice behavior and selected objectives for emissions pricing. The overall idea of typical estimating models is that we use the static traffic assignment model to distrib-ute traffic volume into each link, then calculate emissions through emission estimation model, and finally guide traffic to achieve our desired objective(s) by means of the emissions pricing scheme. These road transport emission evaluation models considering environmental toler-ance not only quantify pollution level into a measurable index generating pricing strategy but also locate critical links conveniently. The model that merges multiple factors with an aim at minimizing emissions plus pricing costs to the public can be understood as a way to minimize the public health costs plus extra fees due to emissions, which is reasonable in reality, while the one on purpose of obtaining the most effective pricing scheme to improve network emis-sion situation should consider actual scenario and its local optimal solution should not be abandoned arbitrarily.This research is originated from the hot discussion over the decades internationally on traffic congestion pricing and reduction in transport emissions. Therefore, the efforts in this thesis may benefit transportation planning and management on road networks in our country.