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.     

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 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.     

Evaluating employer programs encouraging the use of alternate transportation modes: Two studies

Since 1976, major Denver metropolitan area firms have been required to encourage employees to use mass transit, carpooling, bicycling, and other alternate transportation modes to commute to work. The encouragement programs of 36 firms were clearly associated with greater use of alternate transportation modes, with the portion of variance in alternate transportation use explained by differences in employer programs of approximately 15%. The effects of the programs on deterring alternate mode users from returning to solo driving are consistently weaker than their effects on persuading drivers to try alternate transportation modes initially. Recommendations for the conduct of alternate transportation encouragement programs are made, based on these and other results. In addition, two recommendations are made concerning the evaluation of encouragement programs: that aggregate percentage change in alternate transportation use should not be used as the sole measure of success, and that environmental variables such as the availability of and pressure for use of alternate transportation modes should be measured and controlled.     

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.     

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.     

Development of multimodal performance measures for transit systems in New York State

The New York State Department of Transportation was required to certify as to the economy and efficiency of transit operators participating in the State's public transportation operating assistance program. This paper describes the efforts undertaken to meet this mandate.Discussed are past efforts to link performance measures to funding programs; reasons for modifying measures which had been used in previous efforts; and some of the problems and issues raised by the use of such criteria. The paper identifies 15 performance measures being used by New York State in its evaluations, the actual ranges encountered in the transit operations being funded through the state program, and tentative acceptable and desirable levels of those measures which the Transportation Department is using in its evaluation. The role these measures play in the state's operating assistance policy decision process is also described.     

Suburban congestion: Recommendations for transportation and land use responses

Transportation congestion is reaching intolerable levels in many urban and suburban areas in the US. Reliance upon traditional responses, such as transit and new highway capacity, is not working — especially in suburban areas. Although methods for dealing with suburban congestion are often different, there are a number of common features that must be considered in developing short term as well as more permanent and long lasting solutions. In proposing short term solutions, a Menu of Actions is described. It includes transportation actions (the traditional transit and transportation management options) where there are opportunities for getting more out of the existing systems; land use/growth management actions which will result in more rational land use-transportation interactions; financial incentives, to encourage or discourage appropriate actions; more comprehensive and systematic land use and transportation planning; and the organizational and institutional actions required to implement rational solutions.While the Manu of Actions provides a broad array of possible actions to provide relief in the short run, over time the growth in traffic is likely to outpace their effectiveness. Consequently, longer term and often more difficult solutions must be considered and implemented as appropriate. They could include changes in land use development and land use management policies; changes in lifestyle and business practices; improvements through technological innovation; changes in the traditional ways of providing transportation services; and greatly expanded research and development.     

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.     

Joint development at transit stations in the United States

Joint development, as the term is generally used in connection with transit systems in the United States, is real estate development that is closely linked to public transportation services and station facilities, and takes advantage of the market and locational advantages provided by them. Research conducted by LEK Associates for the Urban Mass Transportation Administration (UMTA) suggests that, in addition to helping shape urban growth and land development, joint development is also a surprisingly effective means of increasing transit system ridership and farebox revenues, as well as a source of increasingly significant revenues from the sale or lease of air rights.The completion of nine joint development projects in as many different cities, started under the former Urban Initiatives Program, for example, net additional annual ridership might reach 12000000 one-way trips. Net additional annual farebox revenues might reach over $9000000. This added revenue would be sufficient to repay the $62 million combined UMTA/transit operator investment in the nine projects, exclusive of the costs of the basic transit system improvements around which the projects are planned, in less than six years.Among transit authority-administered joint development programs examined in a separate study, the Washington Metropolitan Area Transit Authority (WMATA) has had the most success in generating significant value capture income. For example, the cumulative revenue realized by WMATA from just six joint development projects in the Washington, DC region, through September 1983 exceeded $ 6.9 million. Projections through fiscal year 1986 indicate cumulative revenues approximating $ 28 million will be received from developer leases.     

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.     

Peak-period traffic congestion: A state-of-the-art analysis and evaluation of effective solutions

This paper reports on an analysis of a range of largely non-construction congestion reduction techniques which was funded by the U.S. National Cooperative Highway Research Program (NCHRP). A number of evaluations of the direct and indirect effec tiveness, costs, timing and feasibility of 22 major classes of promising techniques was performed. Based on this analysis, the study team evaluated 17 of these techniques as both effective and feasible in a U. S. institutional context.However, none of these 17 offered more than marginal reductions in peak-period traffic congestion when applied individually. Some techniques affected so small a percentage of travelers that reductions in congestion would not be discernible. Other techniques promised significant congestion reductions in theory but did not realize that promise in practice. It was concluded that many techniques could be implemented together with the potential for far greater combined effectiveness.An analysis was performed to determine how best to package or jointly implement promising techniques to optimize their combined effectiveness. It was found that all promising techniques could not be applied together because of conflicts in their impact. This analysis suggested eight sample packages or combinations of mutually supportive techniques. These eight packages were subjected to evaluations similar to those performed for individual techniques; while the packages are merely examples of potential combinations, the evaluation methodology employed should be of continuing use to local transportation planners.This paper was developed from NCHRP Report 169, Peak-Period Traffic Congestion, Options for Current Programs, and Peak-Period Traffic Congestion: State-of-the-Art and Recommended Research (NCHRP Agency Draft) By Robert Remak and Sandra Rosenbloom.This study was conducted under National Cooperative Highway Research Program Project 7/10. The opinions and findings expressed or implied in this paper are those of the author. They are not necessarily those of the Transportation Research Board, The National Academy of Sciences, the Federal Highway Administration, the American Association of State Highway and Transportation Officials, nor of the individual states participating in the National Cooperative Highway Research Program.On Leave to the U. S. Department of Transportation, Washington     

The state-of-the-art in urban transportation planning or how we got here

This paper traces the development of urban transportation planning in the United States, focusing particularly on the influence that three previous conferences -Sagamore (1958), Hershey (1962), and Williamsburg (1965) - have had on the course of this development. Included also are comments on the current state of the art of urban transportation planning and observations as to its future direction.The Federal-Aid Highway Act of 1934, which authorized the use of 1 percent funds for highway planning is identified as the progenitor of urban transportation planning in the U.S., and two reports based on information developed by the highway planning surveys first funded under the 1934 Act, Toll Roads and Free Roads (1939) and Interregional Highways (1944), are credited with preparing the ground for much of the urban transportation planning that was to follow.The rapid development of home interview survey techniques in the late 1940's and the full-scale introduction of computer technology in the Detroit Area Transportation Study are noted, as is the work of the National Committee on Urban Transportation, which was initiated in 1954 under sponsorship of the Automotive Safety Foundation. In addition to its substantial technical contributions, the NCUT, through its success in mobilizing the cooperative efforts of virtually every major group concerned with urban transportation, stimulated significant gains in Federal-State-local relationships and paved the way for increased Federal aid to cities in solving their local transportation problems.The impact of the 1956 and 1962 Federal-Aid Highway Acts on urban transportation planning is assessed. The substantial contributions, of the Hartford, Sagamore, Hershey, and Williamsburg conferences are discussed, as are their shortcomings. It is noted that many of our present concerns — environmental impacts, relationships between transportation and land use, need for cooperation among all levels of government, the multi-modal nature of urban transportation, and the need for citizen involvement, to name a few — were incorporated in the provisions of either one or another of the Federal-Aid statutes in the 1950's and 60's or appear in the recommendations of the several conferences. That these matters still concern us today is given as evidence that planning has not fully lived up to its promise and responsibility, that more rather than less planning is needed, and that, above all, new leadership to pick up where the old has left off must soon assert itself.     

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.     

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.     

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.