Sustainability assessment and sustainability indicators are familiar terms that have gained significant importance. Non-compliance between the sustainable development principles and transportation ...infrastructure projects is changing the appearance of historic cities from livable and vibrant atmosphere into the car-oriented condition and cause environmental and social problems. There exist numerous studies on measuring the sustainability of transportation at the country, state, city, and even traffic zone levels, but few have addressed the sustainability of micro-scale projects. The objective of this study is to assess the sustainability of infrastructure projects on urban transportation systems and evaluate their compliance with principles of sustainable development. According to made intensive field visits, run expert interviews, and development master plans relevant to the case study, nine scenarios are proposed to improve the traffic situation of Azadi district in Isfahan city. Obviously, a slight change in the urban streets network, would have a significant effect on traffic performance in larger area, therefore, all the proposed scenarios are modeled in Trans Cad 5.0 software environment to determine their influence area (IA) as the study area. Ten quantitative indicators in three dimensions (environmental, social, and economic) pertinent to the urban transportation are selected based on review of the related literature and available data in Isfahan. The IA and all proposed scenarios are simulated and calibrated in AIMSUN 8.0 environment and the indicators are quantified in a direct and indirect manner through AIMSUN outputs. A composite sustainability index (CSI) is applied for integrating the effects of selected indicators based on their rankings given by the experts regarding to the goals of Isfahan vision in 2025. The results indicate that public transportation development projects are the most compliant scenarios with the principles of urban sustainable development and the best options for the future development in Azadi district. This proposed framework, would assist policy-makers and traffic engineers in other cities to evaluate the sustainability of urban transportation infrastructure projects.
•Present a framework for transportation infrastructure projects sustainability assessment•Determining the influence area (IA) of the case study through Trans Cad 5.0 software•Considering 10 sustainable indicators and quantified through AIMSUN 8.0 abilities and predictive models•Aggregating indicators with respect to the goals of Isfahan vision in 2025•Propose public transportation development projects as the most sustainable scenarios
•A combined usage of microscopic traffic simulation and Extreme Value Theory (EVT) was proposed for safety evaluation.•Three calibration strategies were applied: a base strategy, a semi-calibration ...strategy, and a full-calibration strategy.•EVT-based methods were employed to model both simulated/field conflict data and derive the Estimated Annual Crash Frequency (EACF).•EVT based on the full-calibration strategy appears to be a better choice for simulation-based safety evaluation.
This paper proposes a combined usage of microscopic traffic simulation and Extreme Value Theory (EVT) for safety evaluation. Ten urban intersections in Fengxian District in Shanghai were selected in the study and three calibration strategies were applied to develop simulation models for each intersection: a base strategy with fundamental data input, a semi-calibration strategy adjusting driver behavior parameters based on Measures of Effectiveness (MOE), and a full-calibration strategy altering driver behavior parameters by both MOE and Measures of Safety (MOS). SSAM was used to extract simulated conflict data from vehicle trajectory files from VISSIM and video-based data collection was introduced to assist trained observers to collect field conflict data. EVT-based methods were then employed to model both simulated/field conflict data and derive the Estimated Annual Crash Frequency (EACF), used as Surrogate Safety Measures (SSM). PET was used for EVT measurement for three conflict types: crossing, rear-end, and lane change. EACFs based on three simulation calibration strategies were compared with field-based EACF, conventional SSM based on Traffic Conflict Techniques (TCT), and actual crash frequency, in terms of direct correlation, rank correlation, and prediction accuracy. The results showed that, MOS should be considered during simulation model calibration and EACF based on the full-calibration strategy appeared to be a better choice for simulation-based safety evaluation, compared to other candidate safety measures. In general, the combined usage of microscopic traffic simulation and EVT is a promising tool for safety evaluation.
A roundabout is a highway engineering concept meant to calm traffic, increase safety, reduce stop-and-go travel, reduce accidents and congestion, and decrease traffic delays. It is circular and ...facilitates one-way traffic flow around a central point. The first part of this study evaluated the principles and methods used to compare the capacity methods of roundabouts with different traffic conditions and geometric configurations. These methods include gap acceptance, empirical, and simulation software methods. Previous studies mentioned in this research used various methods and other new models developed by several researchers. However, this paper's main aim is to compare different roundabout capacity models for acceptable capacity predictions for single-lane and multi-lane roundabouts. In conclusion, previous studies such as RODEL, SIDRA, Swiss, HCM6, and IRC overestimate capacity, while the GHCM method underestimates it. Each VISSIM and SIDRA predicted higher capacity than HCM2010, Paramics, and Simtrafic capacity methods. Generally, the precise prediction of capacity value depends on the circulating flow, exiting traffic flow, driver behavior, and geometric variations. Also, a comparison between seventeen methods was made using virtual data. For a single-lane roundabout, Girabase and Swiss models estimated higher capacity values when compared with other models, while HCM 2010 estimated lower capacity. The Shamueli’s model provides an estimate of capacity about the same as the lower bound of the HCM 2000 model. Brilon’s model estimated lower capacity values for a multi-lane roundabout compared with other methods. At low circulating flow, the Girabase model estimated a higher capacity value, while with the increasing circulating flow, the FHWA2000 estimated a higher capacity than the Girabase model. Also, there is a bit of a difference between SIDRA 5 and 8.0. There is a small interval between models that are implemented in a single-lane roundabout. Therefore, the models are better at predicting the capacity of a single lane than they are at predicting the capacity of multiple lanes.
The Smart city is important for sustainability. Governments engaged in developing urban mobility in the smart city need to invest their limited financial resources wisely to realize sustainability ...goals. A key area for such sustainability investment is how to implement and invest in emerging technologies for urban mobility solutions. However, current frameworks on how to understand the impact of emerging technologies aligned with long-term sustainability strategies are understudied. This article develops a simulation-based comparison between different cities and autonomous vehicle (AV) adoption scenarios to understand which aspects of cities lead to positive AV implementation outcomes. As urban mobility and cities will become smart, the analysis represents a first attempt to explore the impact of AVs on a large scale across different cities around the world. Archetypes are formed and account for most, if not all, world cities. For three of our archetypes (car-centric giants, prosperous innovation centers, and high-density megacities), promoting AV-shuttle use would deliver the greatest advantage as measured by improvements in the model's KPIs. To develop urban powerhouses, however, micromobility would deliver greater benefits. For highly compact middleweights, a shift from private cars to other non-AV modes of transportation would be the smartest choice.
•Each smart city has unique needs and resources, which will possibly need diverse and unique strategies.•To realise sustainability goals, governments of the Smart City need to invest the financial resources wisely.•We show the need for different urban mobility solutions across cities.•We identify sustainable investment strategies for urban mobility and autonomous driving.
The significant increase in freight transport during an after the COVID-19 era, is leading to a continuous increase in the number of trucks and their proportion in traffic conditions. The objective ...of the present study is to quantify the impact of trucks on traffic and environmental conditions of a motorway. To achieve this objective, traffic data from Nea Odos Motorway were used for a period of two months in 2021. Within the analysis framework, micro-simulation was used in order to examine impacts mainly on traffic, environment and energy efficiency on network level for different penetration rate scenarios of trucks. Results indicate several insights for the network due to different penetration rates of truks confirming that traffic and environmental conditions are largely affected by freight transport and providing stakeholders and policy makers with important conclusions.
With the increasing demand for the urban traffic simulation, the mesoscopic model takes center stage with its advantage that can simulate a large network with less computational cost and gets the ...information of individual vehicles. This study proposes a mesoscopic traffic simulation model called Agent-based Mesoscopic Cell Transmission Model (AMCTM). It models both longitudinal and lateral movement of vehicles. The longitudinal movement is based on the Cell Transmission Model (CTM) and implements the traffic signal by adjusting the amount of flow between cells according to the signal. The lateral movement includes mandatory lane-change to allow the vehicle to follow the specified route and the optional lane-change to reduce the travel time. To evaluate the proposed model, we conduct the experiment with a test network including signalized intersection. The result of the experiment shows that the AMCTM performs well several phenomena occur in the urban network. This study is expected to contribute to the performance evaluation of the newly developed traffic-related technologies such as autonomous vehicles and V2X communication-based control systems.
Existing methods to improve the operational efficiency and service level of urban rail transit (URT) systems focus on forecasting passenger flow in macro networks and optimizing metro vehicle ...operation strategies. Among the factors affecting passenger comfort in vehicles, the passenger arrival distribution is the most direct but is not sufficiently taken into account. This study provides a riding guidance method for passengers on the URT platform to improve the uniformity of the passenger distribution among carriages. First, a passenger arrival distribution model is proposed on the basis of the influences of the queue length at the door, the number of people in the carriage and the travel distance on the passengers’ choice of carriage. Second, taking the maximum spatial comfort degree of every passenger as an objective, a passenger riding guidance model on the URT platform is proposed. Hefei Metro Line 2 is taken as an example for the numerical case study, and the results show that the guidance method can balance the passenger flow distribution and improve the spatial comfort level of passengers when the passenger flow is approximately 65 to 135 persons per 5 min.
•Propose a passenger arrival distribution model on station platform.•Establish a guidance scheme for the passengers entering the station platform.•The guidance model can improve the passengers’ spatial comfort level in carriages.
Urban traffic networks consisting of partially blocked roads often need to remain open to traffic before, during and after disasters because of their vital roles to hazard preparation, emergency ...response and recovery of urban communities. To conduct effective traffic planning of disrupted transportation networks highly depends on accurate prediction of travel time on partially blocked roads, which is very different from that on intact roads. Due to the lack of appropriate models, travel time prediction approaches developed for intact roads have often been directly applied to partially blocked roads, leading to inaccurate travel time estimates. Unrealistic travel time estimates of partially blocked roads as well as the whole transportation network further affect traffic planning, emergency response and other decision-makings which are heavily reliant on travel time prediction. A new approach to develop travel time functions for partially blocked roads in urban areas is proposed to close this gap based on microscopic traffic simulation. First, an improved model for simulating traffic on partially blocked roads is developed by extending the existing cellular automaton model. Second, the improved traffic model is validated at microscopic and macroscopic levels with measured traffic data from an urban road. Third, traffic simulations under various scenarios with different demand flow rates, truck ratios and blockage ratios are conducted through microscopic simulation experiments. Finally, a set of continuous traffic time functions are further developed for disrupted traffic flow with parameters estimated from the generated traffic data. The developed travel time functions for a typical urban arterial road are then compared with the standard Bureau of Public Roads function. The comparison suggests that the standard Bureau of Public Roads function would considerably underestimate the travel time on partially blocked roads and the proposed travel time functions can offer a more realistic prediction. The proposed methodology of developing the travel time functions of partially blocked roads will be helpful for accurate estimation of traffic demand of post-hazard transportation networks.
•An improved cellular automaton model for traffic flow simulation on disrupted urban arterials is proposed.•The proposed traffic simulation model is calibrated and validated at microscopic and macroscopic levels.•Travel time functions for partially blocked roads in urban areas are developed for the first time.
Loop detectors are probably the widest-used technology for traffic state estimation. Previous research has shown that loop detector positions within the link significantly affect the estimation of ...the macroscopic fundamental diagram (MFD) of a given network. This paper examines the biases produced by the positioning of loop detectors on the MFD, using both analytical and simulation methods, as well as empirical data from UTD19. We confirm earlier results that a uniform distribution of loop detector positions reduces the bias. We discovered that: (i) subsets of the MFD determined by the loop detector position can help estimate whether the loop detector MFD will have a bias; (ii) non-uniform distribution of loop detectors is more likely to cause a discrepancy in the position subsets of the MFD, particularly if detectors in the network are positioned more downstream with a greater variation; and (iii) a lower ratio of link length to green signal time increases the possibility of bias in loop detector MFD, while the impact of the aggregation interval was found to be negligible. This research opens the possibility for the bias of MFD induced by the loop detector data to be corrected by only using itself.
•We examined the biases produced by the loop detector positioning on the MFD.•Subsetting MFD by the loop detector position can aid in estimating bias presence.•The logistic regression model is used to estimate factors that influences MFD bias.•We investigated the impact of link length and aggregation interval on MFD bias through simulation.
Cycling as a mode of transport is on an upward trend as a low-emission alternative to driving in urbanized areas nowadays. With the increasing number of cyclists, it is of great importance to assess ...the capacity of cycling infrastructure in practice. Simulation models are useful tools to investigate bicycle flow performance considering cyclists’ distinct moving behaviors. However, existing bicycle simulation models are restricted by either space discretization, lane-based setup, adaptation from models for car traffic, or complicated calibration requirement in a force-based environment. In addition, cyclists’ decision-making ability in the operational-level cycling behavior are not well-captured in these models. This paper proposes a comprehensible microscopic bicycle simulation model which includes a detailed decision-making process and the ability to simulate continuous-space lateral movement. The model consists of three levels, maneuver decision, movement planning, and physical acceleration. It is able to simulate bicycle flow dynamics in undersaturated traffic conditions on an exclusive bike path. As we do not intend to show the empirical validity of the proposed model, the simulation experiment aims at verifying the model and exploring bicycle flow performance in various scenarios by estimating the fundamental diagrams (FDs). The effect of different path widths on bicycle flow capacity is first explored. Other behavioral factors, including desired speed heterogeneity, overtaking incentive, and safety region size perceived by cyclists, which can potentially influence the shape of the FD are also tested. The model can be further extended to simulate relatively complex cycling behavior with cooperative and anticipative strategies and investigate bicycle flow characteristics in congested traffic conditions.
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