Many cities have integrated their public transportation modes to provide increased accessibility and reduced commute times. However, current transport network topology studies have focused on unimodal networks. Therefore, it is of significant interest for policymakers to examine the topology of integrated public transportation networks and to assess strategies for improving them. The objective of this study was to discuss a comprehensive analysis of an integrated public transportation network using graph theory, compare its characteristics to unimodal networks, and draw insights for improving their performance. Results demonstrate pertinent information concerning the structural composition of the Seoul Metropolitan Area’s (SMA) public transportation network. Despite the integration, the spatial configuration of the network was found to have low fault tolerance. However, the highly agglomerated community structure validated the robustness of integrated networks. Network centrality measures confirmed that integration improves connectivity and spatial accessibility to suburbs within the city. The study found that the SMA’s current public transportation network possesses structural defects that need to be addressed to improve its resilience and performance. Based on the outcomes of this study, the strategic creation or relocation of stations, and the construction of more links, is imperative for the enhancement of mobility.

Assessing ecosystem service values of urban parks can promote understanding of urban green space protection and management. In this study, ecosystem services of air quality purification from 40 sample parks with different areas and land cover compositions were assessed based on literature records and high-resolution images. Six typical ecological benefits of CO₂ sequestration, O₂ generation, air temperature amelioration, SO₂ removal, NO_x removal, and dust interception were estimated. The results showed similar proportions of different ecosystem service values to total. The ecological services of CO₂ sequestration and O₂ generation contributed the majority of total ecosystem service value, with percentages ranging from 69.34% to 73.76% and from 20.52% to 21.71%, respectively. There was very wide variation of ecosystem service values among urban parks. Multivariate regression between ecosystem service values and spatial characteristics of urban parks revealed that park areas of forest and water played a vital role in service value. For a given park, the total service value could be increased by up to 600% if the park was redesigned with consideration of land cover composition. This study provides sound scientific information for urban planners and greening designers to optimize urban park layout.

This study analyzes the impact of autonomous-vehicle (AV) market-penetration rates on traffic-flow safety using a genetic algorithm. We set up a microscopic traffic-simulation scenario on a 640 m section of the US I-101 freeway using VISSIM, a microscopic traffic-simulation software. The results of analyzing the number of conflicts according to the introduction rate of autonomous vehicles showed that the number of conflicts increased as the introduction rate increased up to 30%, and then decreased from 40% or more. In this study, it was assumed that autonomous vehicles can avoid dangerous situations, so it is judged that this is the result of an increase in the traffic volume of autonomous vehicles and a decrease in the traffic volume of conventional vehicles. When planning an exclusive lane for autonomous vehicles, it is judged that it is desirable to install two exclusive lanes on the left side until the introduction rate of autonomous vehicles reaches 30%. When the introduction rate of autonomous vehicles is 40–90%, the risk of accidents between autonomous vehicles and conventional vehicles decreases, and the traffic volume of autonomous vehicles is higher than that of conventional vehicles. Therefore, it is judged that it is desirable to operate a mixed road where autonomous vehicles and conventional vehicles can drive together rather than operating an exclusive lane for autonomous vehicles.

The decision-making behaviors of drivers have been clarified, as various researches on traffic behavior have been conducted until today. However, existing models set limits to examine non-linearity, ambiguity and the errors, which are occurred by variety of space-time contained in human conscious structure and process of decision-making. In particular, it is true that the route choice behavior of drivers is affected by external factors, such as past experience and change in diverse road environment information. However, taking into account the fact that various traffic problems are not being solved, it is proven that there are limitations in clearly describing traffic behavior. Accordingly, in order to construct a model that considers obscurity and non-linearity in the decision-making process of drivers, a model through neural network linkage and genetic algorithm was proposed in this study. In addition, this study was focused on proving the effectiveness of neural network theory and genetic algorithm, and studying the appropriateness of applying them into the field of transportation.

With the advent of Intelligent Transport Systems (ITS), especially over the last decade, considerable researches have been conducted on drivers' responses to Advanced Traveler Information System (ATIS). Some of the results are being used in an operational level. However, still much additional research is needed to identify optimal strategies for providing traffic information to drivers. This study analyzes results of a mailed survey of frequent freeway users in Wisconsin to determine driver response to Variable Message Signs (VMS). Respondents to the survey are quite familiar with VMS and have generally positive attitudes towards VMS and its effectiveness. Factors that perceived usefulness of VMS information have been identified. Regression analysis is used to quantify the relationship between the reliability of VMS information and the number of route adjustments. Other human factor problems such as readability and visibility of VMS have also been found along with some prospective recommendations. Some limitations and future research agenda have also been discussed.