Traffic congestion leads to delays and increased carbon dioxide (CO2) emissions. Traffic management measures such as providing information on environmental route costs have been proposed to mitigate congestion. Multi-criteria routing dynamic traffic assignment (MCR-DTA) models are needed to evaluate the effectiveness of such measures. This paper presents a simulation-based bi-level optimization method to solve the MCR-DTA problem, which works as follows. Route costs include travel times and emissions, but those are updated inside two different loops. In the inner loop, emission costs are considered fixed; the assignment is performed by updating route travel times, using a traditional DTA tool. Then, in the outer loop, emissions are calculated based on link loads and fed back to the DTA tool, which performs a new assignment. The MCR user equilibrium is found when emissions or predefined generalized costs converge to an equilibrium. The bi-level method is first tested on a small network, showing that the proposed method is able to effectively solve the MCR-DTA problem. Next, the method is applied to a medium-size urban network. The results show that if drivers choose routes based on emissions besides travel time, the average travel time and emissions per vehicle decrease. This occurs because congested links have a higher impact on route costs; hence the equilibrium is pushed away from the single-criteria routing (SCR) user optimum towards the SCR system optimum. Results support the conclusion that informing drivers about CO2 emissions per route can potentially lead to decreased delay and emissions in real networks.@en

In internet of vehicle (IOV) system, vehicle-to-vehicle (V2V) data transmission is influenced by multipath interference, which often causes bad consequences. In order to improve the data transmission reliability, a new estimate algorithm is proposed, that is an evaluation algorithm for V2V communication reliability based on sample judgment and balanced modulation. This study structures a transmission channel model of V2V in IOV, and analyses the characteristics of multipath transportation of communication channel. The simulation result indicates that the above-mentioned reliability estimate method can get an even better accuracy of V2V communication transmission and better effect of communication channel balance. Meanwhile, it can also reduce the error code ratio of the communication and improve the communication quality.@en

It is expected that automated vehicles will gradually penetrate on public roads, resulting in mixed traffic in the next decades. This can impact traffic flow operations, especially the roadway capacity and flow stability. It is of paramount importance to understand and predict the implications of automated driving systems on traffic flow at the early design phase to avoid disruptive impacts on traffic. String stability properties of automated vehicle platoons are a fundamental block to understand their traffic flow stability impact. Previous reports on string stability analysis focussed on homogeneous vehicle strings and simplify the time delays in vehicle systems. This work propose an analytical approach to determine string stability conditions for non-connected vehicle platoons with heterogeneous parameters. To this end, a third-order linear vehicle dynamics model is used in the control design and Laplace transform of the spacing and speed error dynamics in time domain to frequency domain enables the determination of sufficient string stability criteria of heterogeneous vehicle strings. The analytical string stability conditions give new insights into the relationship between the string stability properties of vehicle strings in relation to the system properties of time delays and controller design parameters of feedback gains and desired time gap. Analytical results are verified via systematic simulation of both homogeneous and heterogeneous strings. Simulations demonstrate the predictive power of the analytical string stability conditions.@en