The design of bus route systems — An interactive location-allocation approach

An interactive modelling approach is developed to solve the practical problem of bus route network design. Possible bus routes are identified with facilities which can be located. Zones or pairs of zones in the urban area are identified with customers who will be allocated to the established facilities. It is shown that the classical Set Covering Problem is useful under the assumption of fixed demand; the Simple Plant Location Problem is effective under the assumption of demand which is sensitive to the level of bus service provided.     

Modelling car availability,modal split and trip distribution by Monte-Carlo simulation: A short way to integrated models

The model used a Monte-Carlo algorithm to simulate modal split and trip distribution as an interconnected decision process at the individual level. Using census data, the individuals of a planning region are classified into situation groups, which represent significantly different decision situations with respect to socio-demographic position and territorial location. According to the theoretical framework, which emphasises mobility constraints instead of preferences, household structure and sex (time budget and car availability constraints) and work place characteristics (location constraints) are the key variables. For each situation group, decision profiles are empirically determined; these describe car availability, travel time constraints and work place distribution. Modal split and trip distribution are simulated as an interconnected individual decision process, which is stochastically determined by the location of the individual and the decision profile of his situation group.The algorithm is very sensitive and flexible and extremely well suited to electronic processing. An extended and modified version is currently being used in the preparation of regional transporation plans for several German city regions.     

The benefits to the public of vehicle legislation — Attempts to measure the unmeasurable

Although inevitably there are grey areas, a distinction may be drawn between environmental disbenefits arising from vehicles which cause annoyance, such as noise, or loss of peace and quiet, vibration, visual intrusion, severance, and those which endanger life and limb. Legislation implemented to reduce either category will inevitably generate costs.It is suggested that in evaluating legislation relating to environmental nuisance, attempts should be made carefully to measure the benefits, while for legislation when life and limb is involved a cost-effectiveness approach should be adopted. Methods currently available to measure environmental nuisance arising from vehicles, for example opinion surveys, observing the effect of changes in some independent indicator, and simulation exercises are critically examined. Using evidence from the Urban Motorway Committee Reports, Noise Advisory Council, Transport and Road Research Laboratory surveys on the effect of traffic in selected High Streets, and the Realistic Environment Assessment Laboratory, Social and Community Planning Research ping-pong technique, studies of house price differentials, and estimates of willingness-to-pay for exclusion facilities, an attempt is made to highlight the dilemma that while benefits of environmental nuisance legislation should be carefully weighed against the anti-pollution costs, techniques currently available for measuring such benefits are very underdeveloped.Paradoxically there is a far more clear-cut procedure for valuing benefits of policies affecting life and limb. Official accident evaluation policy in the U.K. is described, and legislation affecting life and limb is examined.Finally, difficulties of effectively enforcing legislation of both environmental nuisance and life and limb categories are illustrated.     

Sample size and grouping in the estimation of disaggregate models—A simple case

Using a very simple form of disaggregate model for household car ownership, it appears that two widely held beliefs about disaggregate modelling — that analysis should always be carried out on individual households, and that sample sizes of 500 to 1000 are generally sufficient - are not necessarily valid. Though the results may not be generalizable to the full class of problems to which disaggregate analysis addresses itself, it does seem that more attention needs to be given to the questions of sample size and grouping.In addition, the standard test of goodness of fit (the so-called rho-squared test) is shown to be extremely weak. A far stronger and to some extent complementary, test is to compare the log-likelihood value given by the model with that on the basis of the full or saturated model — a test which has recently been clearly presented by a number of writers in the statistical literature. When using dummy variables, it is important that pair-wise tests on coefficients relating to various levels of the same attribute should be carried out, as well as the standard test assessing difference from zero.These points are illustrated by a number of simple examples.The abstract of this paper appears on p. 369.     

The state-of-the-art of “comprehensive” planning

Planning occurs as a part of governmental operations wherever decision-making happens. For US metropolitan areas, the locuses of decision-making are multiple, ranging in scale from very small jurisdictions up through the hierarchy to state and federal levels, and in function from general governments to many special-purpose agencies — transportation, health care, education, etc. Almost all might affect or be affected by urban transportation decisions and actions. Since no one of these units of government is comprehensive in authority and activity, there is no single, centralized planning operation that is truly comprehensive. Pluralistic planning is increasingly trying to foresee and to accommodate the interactions among the various levels and functions. Instead of fragmenting, with the fragments pulled apart and insulated, we need to move toward partitioning, not merely to delimit boundaries but also to identify interfaces. This movement is hampered by the differentials in the development of the state-of-the-art of the technical planning process now used by the several levels and functional units of government. This is most advanced, and most effective, for small, homogeneous suburban jurisdictions primarily concerned with guiding and controlling physical development; it is in disarray in central cities trying to cope with social and economic problems as well as with physical deterioration; at the metropolitan scale it is highly developed technically but not very influential. There is a trend toward a network of planning activities that recognizes and facilitates interrelationships and interactions, both vertically among functional boundaries and horizontally across geographical-scale distinctions — a trend toward the comprehensive —but we have a very long way to go.Paper prepared for the Highway Research Board Conference on Organization for Continuing Urban Transportation Planning.     

Disaggregate simultaneous urban travel demand models: A brief introduction

This paper is intended to provide a general background to the two following papers, A Simultaneous Destination and Mode Choice Model for Shopping Trips and Some Estimation Results of a Simultaneous Model of Auto Ownership and Mode Choice to Work. Some of the deficiences of the conventional urban transport modelling system are reviewed and a case is made for the use of simultaneous models estimated with disaggregate data.     

A tale of two cities

Land use and transportation mutually affect each other. Unfortunately, most transportation decision making procedures assume that public agencies cannot shape future land use patterns, and that past land use practices unswervingly determine future conditions. In A Tale of Two Cities, the author surveys the correlations between land use policies and travel behavior in two Oregon cities (Portland and Hillsboro).Building on successes the City of Portland has achieved in reducing reliance on the automobile, the author outlines a recent project by 1000 Friends of Oregon, titled Making the Land Use, Transportation, Air Quality Connection (LUTRAQ). According to the author, the purpose of LUTRAQ is to replicate Portland's approach in a more suburban context. Specifically, LUTRAQ is attempting to develop a realistic land use/transportation/demand management alternative to a proposed new bypass freeway and to accurately measure that alternative for its effects on travel demand, land use, air quality, climate change, and other indices. Although LUTRAQ is a project in progress, the author provides preliminary information that suggests the alternative successfully reduces demand for single occupancy automobile travel.     

An assignment model with modified Logit,which obviates enumeration and overlapping problems

One of the main components of stochastic assignment models is the route choice model solved with implicit or explicit path enumeration algorithms. Such models are used both for congested networks within equilibrium or dynamic models and for non-congested networks within static or pseudo-dynamic network loading models. This paper proposes a C-Logit model specification within a Dial algorithm structure for the implicit assignment of network flows. The model and its solution algorithm, called D-C-Logit, combine several positive features found in the literature for choice set generation and choices from a given choice set: generation of a set of alternatives with a selective approach; calculation of the path choice probability in a closed form; simulation of the overlapping effect among alternative paths; computation of just one tree for each origin avoiding explicit path enumeration.This paper has two main objectives: the proposition of a Dial-like algorithm to solve a C-Logit assignment model and application of the algorithm to different networks in order to demonstrate certain properties.     

Model development for metro station access mode choice

This paper analyses the behaviour of metro users in choosing their access mode to a metro station. Multinominal logit models with satisfactory predictive power were developed for access mode choice on the basis of data collected by interviewing metro users at existing metro stations. A population segmentation approach was adopted and models referring to individuals having the same set of alternative access modes were developed. Trip purpose was found to have significant effects on the access mode choice. Thus, for each population segment different models are proposed for work and education and other trip purpose. Various conclusions concerning the importance of the variables included in the proposed models were drawn through comparisons carried out across the models.     

Wanting to travel,more or less: Exploring the determinants of the deficit and surfeit of personal travel

This study investigates the determinants of peoples desire to increase or decrease the amount of travel they do. We use data from 1,357 working commuters, residents of three different neighborhoods in the San Francisco Bay Area, California. The dependent variables are indicators of Relative Desired Mobility for ten categories of travel (short- and long-distance overall and by several mode- and purpose-specific categories). These variables are measured on a five-point ordinal scale ranging from much less to much more, through which the respondents indicated the amount of travel they want to do (in the category in question) compared to what they are doing now. Censored ordered probit models were developed for these variables, with explanatory variables including general travel attitudes, specific liking for travel in each of the same separate categories, objective and subjective measures of the amount currently traveled in each category, and personality, lifestyle, and socio-demographic characteristics. The results support the hypotheses that the liking for travel has a strong positive impact, and subjective qualitative assessments of mobility have a strong negative impact, on the desire to increase ones travel. Finally, a number of general types of effects on Relative Desired Mobility were identified, among them complementarity and substitution effects. The results of this study can provide policy makers and researchers with new and valuable insight into key principles that affect individual travel demand.     

The Market for Transportation-Land Use Integration: Do Developers Want Smarter Growth than Regulations Allow?

Transportation and land use research of the past decade has focused in large part on the question of whether manipulating land uses in the direction of smart growth alternatives can reduce vehicle miles traveled (VMT) or otherwise improve travel behavior. Yet the notion of manipulating land uses implies that the alternative is somehow self-organized or market-based. This view appears to underestimate the extent to which current planning interventions in the United States – largely focused on lowering development densities, mandating ample road and parking designs, and separating land uses – impose an auto-oriented template on most new development. Rather than a market failure, the paucity of smart growth alternatives may be a planning failure – the result of municipal regulatory exclusion. This problem definition would shift the burden of proof for policy reform, as uncertainty in travel-behavior benefits would hardly justify the continuation of exclusionary regulations. If municipal regulations in fact constrain alternatives to low-density, auto-oriented development, one would expect developers to perceive unsatisfied market interest in such development. This article studies, through a national survey (676 respondents), US developers' perceptions of the market for pedestrian-and transit-oriented development forms. Overall, respondents perceive considerable market interest in alternative development forms, but believe that there is inadequate supply of such alternatives relative to market demand. Developer-respondents attribute this gap between supply and demand principally to local government regulation. When asked how the relaxation of these regulations would affect their product, majorities of developers indicated that such liberalization would lead them to develop in a denser and more mixed-use fashion, particularly in close-in suburban locales. Results are interpreted in favor land-policy reform based on the expansion of choice in transportation and land use. This view contrasts with a more prevalent approach which conditions policy interventions on scientific evidence of travel-behavior modification.     

New methods of controlling vehicle ownership and usage in Singapore

Over the years Singapore has introduced several fiscal measures aimed at restraining car ownership and usage and thus preventing traffic congestion. Two new methods have recently been added: the Vehicle Quota System which limits the number of new vehicles registered each month and the Weekend Car Scheme which allows cars to be registered for use during off-peak hours only, with substantial financial savings to the owners. The Vehicle Quota System involves monthly public tenders for Certificates of Entitlement needed to register new cars. Over the past 30 months the cost of COE's has been increasing and now constitutes between 12% and 27% of the on-the-road price of a new car. The fluctuations in the COE premiums for different vehicle categories are presented and analysed. The initial problems and the recent modifications made as a result of public pressure are also described. It seems that the increases in COE premiums are likely to continue under strong economic growth conditions as the demand for cars is more income-elastic than price-elastic.     

Teleworking in the Netherlands: an evaluation of changes in travel behaviour

This article describes the first experiment on teleworking in the Netherlands, and presents the results of an analysis of the impact of teleworking on the travel behaviour of the participants in the experiment and their household members. It was concluded that teleworking has resulted in a significant decrease in the total number of trips by teleworkers (–17%). Peak-hour traffic by car has been reduced even more (–26%). An unexpected result was that the household members of the teleworkers also appeared to travel less than before the experiment.     

Approaches to the future in U.S. urban transportation planning

In appreciation of the fact that longer-run considerations are particularly important in the development of urban transportation, during the past three decades American transportation planning has been employing increasingly sophisticated approaches to the future. This article discusses four phases in this evolution, with a given focus dominant in each period.During the first period, following on the initial provision of federal government funds for the construction of highways in and around cities, major reliance was based on simple projections of travel demand in metropolitan regions, based mainly on current patterns.This was followed by an approach which focused on an analysis of impacts on transportation systems of projected land uses, based on forecasts of population and economic growth for a target year, on the assumption that facilities were to be provided to move all vehicles that wanted to move from here to there at least possible cost.The third period was characterized by an increasing consciousness of the value of articulating national and local goals in making transportation decisions, going beyond narrow economic and mobility objectives, and including the notion of trade-offs among goals.The most recent period discussed is one characterized by rising interest in futures studies, using methods such as Delphi and cross-impact analysis and approaches such as alternative futures, as well as a search for achieving flexibility in transportation development and for means of limiting resource commitment in the face of the uncertainties of the future (keeping options open).It is pointed out that we still have a long way to go in learning how to evolve feasible images of the future, with associated explicit urban life-style goals, that come to grips with societal variety and conflicting interests.     

What is induced traffic?

Investment in new or up-graded roads both raises the level and alters the pattern of accessibility over the whole area served by the road system. Vehicle-users will perceive the opportunities that this increased accessibility offers and respond in various ways, most of which can lead to more rather than less travel on the system. To the extent that travel increases overall, it can be said to have been induced by the road-improvement. Conversely, congestion as it spreads on the network will deter some travel and can be said to have a traffic suppression effect.The purpose of this first paper is to spell out, as clearly as possible, what is meant by induced traffic and to relate its various components to the full range of behavioural responses by travellers. In doing so, it draws upon the recently published (December 1994) report by the Standing Advisory Committee on Trunk Road Assessment (SACTRA) and response by the UK Government. The paper concludes with some of the implications of induced/suppressed traffic for current methods of forecasting and evaluation of road investment, which are covered in more detail by subsequent authors.     

Gateway diversity and competition in international air transportation

Because of the existence of limited designation gateways, i.e., gateways for international air travel where entry by U.S. flag carriers is limited (in many cases to only one carrier), the U.S. Civil Aeronautics Board (CAB) has announced a policy of gateway competition. This policy seeks to maximize inter-gateway competition as a goal of the carrier selection process. The paper reviews the rationale and history of this policy and the economic principles of gateway competition. After addressing exceptions where gateway competition does not enhance competitive goals, the issue of how to enforce the credibility of the bidding process in route awards is addressed. The paper concludes by identifying circumstances where competitive objectives are not advanced through application of the principle gateway competition.     

Allocation of funds to public transport investment and operating support

This paper reviews the present levels of operating support to, and public investment in, public transport systems in Western Europe. All internal bus, tram and rail services are included, and estimates made for total support in Britain, Sweden, West Germany, the Netherlands and France. To make comparison meaningful, these are shown in relation to GDP and traffic carried. Support levels in Britain are below average, but by no means the lowest as sometimes assumed. Reasons for providing support are considered, including existence of financial burdens arising historically, assistance to particular groups of users, problems in price discrimination and inability of other modes' charges to reflect costs. The extent to which support payments may merely subsidise inefficiency is outlined. A distinction is drawn between productive efficiency, i.e. the resources used to provide a specified level of service and fare, and allocative efficiency, i.e. the extent to which resources are allocated so as to maximise traffic, etc. The extent for reducing support yet retaining the present general level of service and fare is considered.Means of raising finance for support are outlined, including relative roles of central and local government. The scope of local taxes being raised to meet local objectives is considered, notably in the French versement transport: In conclusion, it is suggested that trunk inter-city services should cover all costs from fares, by a discriminatory pricing policy, but central government provide a basic support level for rural areas. In urban areas, practical limits exist to price discrimination, and the best policy may be collective purchase of facilities through a local tax.     

Market segmentation as a mechanism in allowing for variability of traveller behaviour

A major problem with aggregate transport planning models is the accounting of variability in traveller behaviour when the basic unit of analysis is the geographical traffic zone. In an attempt to allow for this variance, recent attention has been given to the role of socio-economic (user and household) characteristics in systematically identifying a homogeneous grouping of travellers with respect to the issue under study rather than restricting the grouping definition according to physical geographical criteria alone. This homogeneous grouping criterion combined eventually with a necessity to represent travel demand in a spatial context, can assist in improving our ability to explain real travel patterns by the development of an improved aggregation condition. The emphasis is on modelling homogeneous groups of travellers separately, and then relating the individual sets of results to each other to obtain an aggregate prediction of behaviour via a knowledge of the representativeness of each group contained in the total sample. This paper presents a technique to identify the relative homogeneity of travellers in accordance with a specified criterion, and illustrates its use with individual household data for the Sydney Metropolitan Area. The paper concludes with a discussion of the advantages of segmentation in operational transport planning, in particular with reference to the aggregation of disaggregate behavioural travel choice models, or movement from a micro-model of individual choice behaviour to an aggregate model of travel demanu.     

Land rents and transport improvements: Some urban parables

Define a transportation improvement's impact zone as the area within which resident households and business firms regularly utilize the improvement. Three simple parables suggest that the increases in impact-zone land rents that usually accompany improvements do not accurately reflect its benefits. Seemingly modest variations in the demand and supply relationships that characterize impact-zone residents can have major effects on the relationship between benefits received and the land-rent changes that are measured. Generally speaking, increases in impact-zone land rents substantially understate benefits unless these benefits are small either absolutely (because the improvement is modest) or relatively (because the impact zone is part of a homogeneous area of much larger size).     

A test of the two-mode UMOT in the Netherlands

The UMOT model, presented as an alternative to conventional travel demand models, is critically examined for its feasibility to predict vehicle distance travelled and average daily traffic in The Netherlands. Using data from the National Travel Survey (OVG) 1978 a Dutch version of UMOT is developed, and an attempt is made to validate it on historical data from the period 1960 to 1980. Some comparisons are made with results of similar work using 1976 survey data in the UK by the Transport and Road Research Laboratory.