In this paper, we propose a control and optimization framework to reduce network-wide emissions in an urban traffic network. The framework is comprised of two layers. The first layer (optimal green routing) predicts the optimal splitting coefficients for all Origin–Destination (OD) pairs crossing the city center or bypassing. As implementing optimal routing strategies on the field is almost impossible as we do not have direct control over the user’s decisions, we choose to balance travel time through gating at the city perimeter so that the usual Dynamic User Equilibrium (DUE) discipline matches the optimal splitting coefficients. The second layer then adjusts inflows at the city gates to the DUE solution based on the instantaneous travel times corresponding to the optimal routing strategy for each OD pair. The accumulation-based Macroscopic Fundamental Diagram (MFD) model of a single reservoir city with seven arterial routes and six bypass alternatives is developed. A Linear programming problem is formulated to determine the optimal splitting coefficients and a Nonlinear Model Predictive Control (NMPC)-based gating control strategy is designed to track the optimal splitting coefficients. The network-wide emission control framework is compared to three other gating strategies aiming to (i) optimize traffic conditions or (ii) minimize emissions, in the inner-city only, and (iii) optimize traffic conditions in the whole network. A comprehensive analysis conducted on all four approaches is presented. We compare the results of the controlled case with respect to the uncontrolled case and with respect to each other. The comparison results show that: (i) the proposed network-wide emission control strategy significantly outperforms the other two simpler control strategies focusing on inner-city only in reducing the total emission, (ii) but also improves the in total time spent and mean speed at the network-level.

在本文中，我们提出了一种控制和优化框架，以减少城市交通网络中的全网排放。该框架由两层组成。第一层（最佳绿色路由）预测穿过城市中心或绕过道路的所有“起点-目的地”（OD）对的最佳分割系数。由于我们无法直接控制用户的决策，因此几乎不可能在野外实施最佳路由策略，因此我们选择通过在城市边界进行选通来平衡旅行时间，以使通常的动态用户平衡（DUE）规则与最佳拆分相匹配系数。然后，第二层根据与每个OD对的最佳路由策略相对应的瞬时旅行时间，调整城市大门处DUE解决方案的流入量。建立了具有七个主干路线和六个旁路选择的单个水库城市的基于累积的宏观基本原理图（MFD）模型。制定了线性规划问题来确定最佳分裂系数，并设计了基于非线性模型预测控制（NMPC）的门控控制策略来跟踪最佳分裂系数。将网络范围内的排放控制框架与其他三个选通策略进行了比较，目的是（i）优化交通条件或（ii）最小化排放（仅在城市内部），以及（iii）优化整个网络的交通条件。介绍了对所有四种方法进行的综合分析。我们将受控案例与非受控案例以及彼此之间的结果进行比较。比较结果表明：