Modelling passengers,buses and stops in traffic microsimulation: review and extensions

In the last decade, significant research efforts and technology have been dedicated to the development of microsimulation tools for a better representation of traffic systems. As a result, several commercial packages appeared and they are used nowadays in the detailed modelling of different transportation systems and operations for specific project evaluations and local designs, mostly within the urban context. After reviewing the specialized literature, we realized that most of these microsimulation tools are oriented to the movement of cars, leaving the public transportation systems as a complement, just for a realistic representation of the transportation system as a whole, but always oriented to simulate cars. In this paper, the objective is to provide guidelines on how to incorporate the necessary entities and components for a proper simulation of public transport systems in a microsimulation environment. Thus, the different approaches to simulate transit systems at a microlevel are discussed, highlighting the necessity of including stops, passengers and transit vehicles explicitly as entities within the microsimulation environment, for modelling transfer operations, control strategies, etc. Several examples are then provided to quantify the impact of such representations, for different cases and potential simulation platforms. Copyright © 2010 John Wiley & Sons, Ltd.     

Alterations to the transyt-7F model to represent near-side transit stops

Transit vehicles stopping to load/unload passengers on-line at a signalized intersection can obstruct the flow of other vehicles. The TRANSYT model ignores the delay to other traffic caused by this loading/unloading process. This can cause TRANSYT to use incorrect flow profiles, resulting in signal timings that cater to these profiles rather than the actual ones. This paper describes a new model for representing near-side transit stops in lanes shared by public transit and private vehicles, and its implementation into the TRANSYT-7F program. The results of an initial application of the proposed model are also described. The proposed model, which is a deterministic simulation model, is able to represent the effect of near-side transit stops on the other traffic; this representation covers both total and partial blockage of the approaches during the transit loading. The procedure has been incorporated into the TRANSYT-7F program. This allows appropriate representation of the adverse effects of transit loading on-line during a green phase. It thus encourages the TRANSYT optimizer to push transit loading to the red phases.     

Modelling and simulation of transportation system effectiveness to reduce traffic congestion: a system dynamics framework

ABSTRACT

This paper is designed to evaluate and improve the effectiveness of transportation systems and reduce traffic congestion through the use of simulation models and scenario development. A system dynamics framework is used to test and evaluate the alternatives of future strategies for the city of Surabaya, Indonesia. Some factors affecting the effectiveness of transport systems include operational effectiveness and service effectiveness, as well as uncertainty. To improve the effectiveness of transportation systems, several strategies can be implemented, such as subsidizing public transportation, increasing the cost of private vehicle parking fees, raising taxes on private vehicles, and reducing delays in public transportation through scenario development. Scenario results show that, by pursuing these strategies, effectiveness could be improved by 80% as the impact of the increase in operational and service effectiveness, helping to mitigate traffic congestion. Congestion could be reduced to 70% (on average) due to the decrease in daily traffic.     

Empirics of multi-modal traffic networks – Using the 3D macroscopic fundamental diagram

Traffic is multi-modal in most cities. However, the impacts of different transport modes on traffic performance and on each other are unclear – especially at the network level. The recent extension of the macroscopic fundamental diagram (MFD) into the 3D-MFD offers a novel framework to address this gap at the urban scale. The 3D-MFD relates the network accumulation of cars and public transport vehicles to the network travel production, for either vehicles or passengers. No empirical 3D-MFD has been reported so far.In this paper, we present the first empirical estimate of a 3D-MFD at the urban scale. To this end, we use data from loop detectors and automatic vehicle location devices (AVL) of the public transport vehicles in the city of Zurich, Switzerland. We compare two different areas within the city, that differ in their topology and share of dedicated lanes for public transport. We propose a statistical model of the 3D-MFD, which estimates the effects of the vehicle accumulation on car and public transport speeds under multi-modal traffic conditions. The results quantify the effects of both, vehicles and passengers, and confirm that a greater share of dedicated lanes reduces the marginal effects of public transport vehicles on car speeds. Lastly, we derive a new application of the 3D-MFD by identifying the share of public transport users that maximizes the journey speeds in an urban network accounting for all motorized transport modes.     

Analyzing year-to-year changes in public transport passenger behaviour using smart card data

In recent years, there has been increased interest in using completely anonymized data from smart card collection systems to better understand the behavioural habits of public transport passengers. Such an understanding can benefit urban transport planners as well as urban modelling by providing simulation models with realistic mobility patterns of transit networks. In particular, the study of temporal activities has elicited substantial interest. In this regard, a number of methods have been developed in the literature for this type of analysis, most using clustering approaches. This paper presents a two-level generative model that applies the Gaussian mixture model to regroup passengers based on their temporal habits in their public transportation usage. The strength of the proposed methodology is that it can model a continuous representation of time instead of having to employ discrete time bins. For each cluster, the approach provides typical temporal patterns that enable easy interpretation. The experiments are performed on five years of data collected by the Société de transport de l’Outaouais. The results demonstrate the efficiency of the proposed approach in identifying a reduced set of passenger clusters linked to their fare types. A five-year longitudinal analysis also shows the relative stability of public transport usage.     

Measuring crowding-related comfort in public transport

ABSTRACT

In this paper we focus on the estimation of crowding in public transport – specifically urban rail systems – and its effect on perceived comfort. It is different from similar studies in the method it employs for estimating crowding levels in vehicles. Specifically, we formulate a function of time and location, which uses only passenger embarking data to estimate the number of passengers in vehicles. Then we convert the estimated crowding values into perceived discomfort levels by trip section. Our method depends on hourly seasonality assumptions but provides good estimates of crowding in urban rail systems even when passenger alighting data is not available. We illustrate the implementation of our model with the example of the Istanbul Metro system.     

A State-of-the-Art Review of Car-Following Models with Particular Considerations of Heavy Vehicles

Abstract

Car-following (CF) models are fundamental in the replication of traffic flow and thus they have received considerable attention. This attention needs to be reflected upon at particular points in time. CF models are in a continuous state of improvement due to their significant role in traffic micro-simulations, intelligent transportation systems and safety engineering models. This paper presents a review of existing CF models. It classifies them into classic and artificial intelligence models. It discusses the capability of the models and potential limitations that need to be considered in their improvement. This paper also reviews the studies investigating the impacts of heavy vehicles in traffic stream and on CF behaviour. The findings of the study provide promising directions for future research and suggest revisiting the existing models to accommodate different behaviours of drivers in heterogeneous traffic, in particular, heavy vehicles in traffic.     

Exposure to noise inside transit buses in Kuwait: Measurements and passenger attitudes

Noise levels were measured, for the first time, inside 115 randomly selected transit buses, operating on 12 sample representative routes in Metropolitan Kuwait. Simultaneously with the monitoring of noise levels, the attitudes of 679 riders concerning the annoyance and long-term health impacts of noise were also surveyed. The noise and passenger attitude data were collected over 10 months (March - December 2000). The percentile distribution, equivalent noise level, traffic noise index and noise pollution levels inside four types of transit buses are presented. Riders' perceived annoyance and awareness of the long-term health impacts of noise were also determined and are discussed. The level of service and performance deficiencies of the public transit system in Kuwait, as perceived by its passengers, are also identified. A number of recommendations end the paper.     

Bus rapid transit systems: a comparative assessment

There is renewed interest in many developing and developed countries in finding ways of providing efficient and effective public transport that does not come with a high price tag. An increasing number of nations are asking the question—what type of public transport system can deliver value for money? Although light rail has often been promoted as a popular ‘solution’, there has been progressively emerging an attractive alternative in the form of bus rapid transit (BRT). BRT is a system operating on its own right-of-way either as a full BRT with high quality interchanges, integrated smart card fare payment and efficient throughput of passengers alighting and boarding at bus stations; or as a system with some amount of dedicated right-of-way (light BRT) and lesser integration of service and fares. The notion that buses essentially operate in a constrained service environment under a mixed traffic regime and that trains have privileged dedicated right-of-way, is no longer the only sustainable and valid proposition. This paper evaluates the status of 44 BRT systems in operation throughout the world as a way of identifying the capability of moving substantial numbers of passengers, using infrastructure whose costs overall and per kilometre are extremely attractive. When ongoing lifecycle costs (operations and maintenance) are taken into account, the costs of providing high capacity integrated BRT systems are an attractive option in many contexts.     

A study of traveler behavior under traffic information-provided conditions in the Beijing area

ABSTRACT

The quality of traffic information has become one of the most important factors that can affect the distribution of urban and highway traffic flow by changing the travel route, transportation mode, and travel time of travelers and trips. Past research has revealed traveler behavior when traffic information is provided. This paper summarizes the related study achievements from a survey conducted in the Beijing area with a specially designed questionnaire considering traffic conditions and the provision of traffic information services. With the survey data, a Logit model is estimated, and the results indicate that travel time can be considered the most significant factor that affects highway travel mode choice between private vehicles and public transit, whereas trip purpose is the least significant factor for private vehicle usage for both urban and highway travel.     

Unconventional funding of urban public transport

In the past decade public authorities have developed a wealth of creative funding mechanisms to support transit systems. This paper offers a taxonomy of various unconventional funding mechanisms (i.e. outside the domain of charges for transit passengers or general taxation schemes), based on a review of financial arrangements for public transport. The paper identifies which classes of funding are particularly successful for the financing of transit systems. This cross-sectional analysis uses a type of artificial intelligence method, viz. rough set analysis. It appears that the nature of the funding scheme and the degree of public acceptability are mainly responsible for the success of unconventional funding mechanisms.     

Cooperation in transit delivery in West German metropolitan areas

West Germany is densely populated, averaging 245 inhabitants/km², but varying widely between urban agglomerations and rural areas. Transport volume has increased by 40% since 1970, with virtually all growth due to private automobiles. Since 1981 public transit has been suffering from decreasing demand.A 1964 Expert's Report to the German federal government was the stimulus for initiating an effective funding mechanism for new public transit construction. In 1965 Germany's first federated transit authority was founded for the region of Hamburg.Principal among the goals of any cooperative agreement among transit companies are improvements for the passengers and improvement of revenues for the companies. To attain these ends, two distinct forms of transit aggrements have been developed in Germany: transit cooperative (Verkehrsgemeinschaft) and transit federation (Verkehrsverbund). The former is more suitable for smaller to medium-sized towns, while the latter is more suitable for larger cities. The two types are described in this article.German transit federations during the 1970s succeeded in significantly increasing ridership, while during the 1980s patronage has either remained steady or has declined. Yet transit federations showed much better perfomance than did public transit in general. In terms of costs and revenues, no public transit organization in Germany is able to break even; deficits vary between 42% and 55%. The author concludes, however, that hidden subsidies for automobile traffic are far higher, because of environmental damage and the high social cost of traffic accidents.     

Water transit and excess travel: discrete choice modelling of bus and ferry trips in Brisbane,Australia

Recent investment in urban ferry transport has created interest in what value such systems provide in a public transport network. In some cases, ferry services are in direct competition with other land-based transport, and despite often longer travel times passengers still choose water transport. This paper seeks to identify a premium attached to urban water transit through an identification of excess travel patterns. A one-month sample of smart card transaction data for Brisbane, Australia, was used to compare bus and ferry origin–destination pairs between a selected suburban location and the central business district. Logistic regression of the data found that ferry travel tended towards longer travel times (OR?=?2.282), suggesting passengers do derive positive utility from ferry journeys. The research suggests the further need to incorporate non-traditional measures other than travel time for deciding the value of water transit systems.     

Representing stochastic transit dwell times in traffic signal optimization

It has been demonstrated that while the TRANSYT traffic model simulates transit vehicles in mixed traffic operation, it does not adequately consider the effects of bus or streetcar stops on the travelled roadway near signalized intersections. Its assumption that the transit vehicles do not hold up other vehicles while they are loading and unloading passengers is also invalid when midblock stops occur in the travelled lanes. To account for the effects of transit stops, an alternative type of network formulation which uses dummy nodes and dummy links with appropriate link costs is proposed for modelling the effects of transit stops. It approximates transit stop dwells by discrete distributions, requiring 1 dummy node and 4 dummy links for each nonzero value used in the approximating distribution. Realism for such operation can be improved significantly, usually with the use of only 1 or 2 dummy nodes per transit stop. Parameters for the dummy links have been tested over a wide range, and a set of operational values is recommended. Flow profiles illustrating the need for and the effects of the recommended formulation are presented in the paper.     

Recent developments in traffic flow modeling using macroscopic fundamental diagram

ABSTRACT

This paper presents an overview of the recent developments in traffic flow modelling and analysis using macroscopic fundamental diagram (MFD) as well as their applications. In recent literature, various aggregated traffic models have been proposed and studied to analyse traffic flow while enhancing network efficiency. Many of these studies have focused on models based on MFD that describes the relationship between aggregated flow and aggregated density of transport networks. The analysis of MFD has been carried out based on experimental data collected from sensors and GPS, as well as simulation models. Several factors are found to influence the existence and shape of MFD, including traffic demand, network and signal settings, and route choices. As MFD can well express the traffic dynamics of large urban transport networks, it has been extensively applied to traffic studies, including the development of network-wide control strategies, network partitioning, performance evaluation, and road pricing. This work also presents future extensions and research directions for MFD-based traffic modelling and applications.     

Validating and improving public transport origin–destination estimation algorithm using smart card fare data

Smart card data are increasingly used for transit network planning, passengers’ behaviour analysis and network demand forecasting. Public transport origin–destination (O–D) estimation is a significant product of processing smart card data. In recent years, various O–D estimation methods using the trip-chaining approach have attracted much attention from both researchers and practitioners. However, the validity of these estimation methods has not been extensively investigated. This is mainly because these datasets usually lack data about passengers’ alighting, as passengers are often required to tap their smart cards only when boarding a public transport service. Thus, this paper has two main objectives. First, the paper reports on the implementation and validation of the existing O–D estimation method using the unique smart card dataset of the South-East Queensland public transport network which includes data on both boarding stops and alighting stops. Second, the paper improves the O–D estimation algorithm and empirically examines these improvements, relying on this unique dataset. The evaluation of the last destination assumption of the trip-chaining method shows a significant negative impact on the matching results of the differences between actual boarding/alighting times and the public transport schedules. The proposed changes to the algorithm improve the average distance between the actual and estimated alighting stops, as this distance is reduced from 806 m using the original algorithm to 530 m after applying the suggested improvements.     

The taxi's role in urban America: Today and tomorrow

Changes in the economic and demographic characteristics of US cities over the past two decades have modified but have not diminished the need for extensive public transportation service in these areas. The vast bulk of trips to work, to shop, and for most other purposes within large American cities are still made by residents of those cities, a significant portion of whom do not own or have access to an automobile. Expensive and far-ranging programs to enhance surburban commutation to the central city by means of rail rapid transit do little to meet the needs of those who still must rely upon local, extensive service within the city.One form of public transport — the taxicab — offers the quality and flexibility of service which even those of limited means find well worth the price. As a consequence, fleet taxicabs serve almost 40 percent more passengers than all US rapid transit systems and about 60 percent as many passengers as all bus transit systems. Removal of archaic and restrictive regulations governing the number and use of taxicabs in major US cities would promote more effective and widespread use of this, the only form of public transit that still operates — at a profit — without public subsidy.     

The principles of calibrating traffic microsimulation models

Traffic microsimulation models normally include a large number of parameters that must be calibrated before the model can be used as a tool for prediction. A wave of methodologies for calibrating such models has been recently proposed in the literature, but there have been no attempts to identify general calibration principles based on their collective experience. The current paper attempts to guide traffic analysts through the basic requirements of the calibration of microsimulation models. Among the issues discussed here are underlying assumptions of the calibration process, the scope of the calibration problem, formulation and automation, measuring goodness-of-fit, and the need for repeated model runs.

Appropriate mass transit for developing cities

This paper is concerned with the majority of developing nations who lack large resources for public sector projects. It questions the basis of much mass transit planning and attempts to put forward a more efficient way of reaching decisions. It calls extensively on experience of Metro Manila, capital of the Philippines, where an innovative system of metropolitan planning and administration is throwing a new light on ‘appropriate’ investment in such developing cities.

Mass transit systems as currently conceived in such developing cities—fully segregated rail‐based systems—are unlikely to be affordable (at least for many years) and in consequence scarce resources should not be devoted to developing and evaluating them. Rather, the principal objective should be to provide low‐cost, affordable mass transit—affordable to governments and to passengers. This almost certainly points to road‐based systems, or predominantly at‐grade light rail transit (LRT) systems, which are usually regarded as ‘obviously unworkable’ in developing city environments.

This judgement is questioned and it is suggested the potential of LRT to provide appropriate low‐cost mass transit is not being realized. An approach to determining its potential applicability is proposed. If feasible it should be evaluated against road‐based systems before decisions to implement new mass transit systems are taken.

While circumstances vary between countries the central message of this paper—that public sector resources have a very high opportunity cost which make all but the lowest‐cost mass transit systems very difficult to justify—will hold in all but the higher‐income developing economies.