Japan Transport Research Institute

Abstract This study validates the continuum traffic flow model of capacity drop at sag and tunnel bottlenecks, as proposed by Jin (Transp. Res. B Methodol. 107 , 41–56, 2018) and Wada et al. (Transp. Res. C Emerg. Technol. 113 , 260–276, 2020), through empirical analysis. Specifically, after addressing the limitations in the existing studies, we calibrate the model using data from multiple congestion events at several expressway bottlenecks. We then demonstrate that the model can reproduce the observed speed recovery near the head of the queue, and assess whether both estimated bottleneck capacities and locations are consistent with observed traffic conditions. Finally, as an application of the calibration results, we examine the relationship between the spatial changes in the estimated traffic capacity and longitudinal gradients.

This study shows how to measure CO2 emissions caused by railways during its life span from construction to disposal. It is now a common global concern that CO2 reduction is vital for conserving the global environment. Amidst this growing awareness, rail transport has attracted significant attention as an environmentally-friendly transportation mode due to its low emission of CO2 gas. But in many studies the amount of CO2 is calculated only during operation and doesn’t include emissions during the phase of construction of related infrastructure and rolling stocks. Rail transport can not be a truly environmentally-friendly transportation mode if it isn’t proven to emit less gases compared with other modes during a modes whole life cycle. In this paper, we introduce the method to calculate CO2 emission from the construction of infrastructure with the application of Life Cycle Assessment (LCA) and the result of a case study.

Abstract This paper looks at the effect of the lubricant on emissions of paniculate matter. A short literature review is presented, together with experimental results for an engine operating with a synthetic lubricant and a defined fuel. The influence of engine operating parameters such as engine load and speed on particulate matter (PM) emissions is discussed, based on measurement of the composition of the aliphatic fraction of the soluble organic fraction (SOF) of the PM. Based on the results from the experiments, which include some comparative data for a mineral‐based lubricant, it is concluded that the method that is generally used to estimate fuel and lubricant contribution to the SOF of the PM has to be reconsidered.