Mogens Fosgerau

A Practical Test for the Choice of Mixing Distribution in Discrete Choice Models

Reference TRANSP-OR-CONF-2006-021 URL: http://transp-or.epfl.ch/documents/proceedings/FosgBier06.pdf URL: http://www.strc.ch/pdf_2006/Fosgerau_Bierlaire_STRC_2006.pdf Record created on 2008-02-15, modified on 2017-10-16

PETRA — An Activity-based Approach to Travel Demand Analysis

This paper concerns the PETRA model developed by COWI in a project funded by the Danish Ministry of Transport, the Danish Transport Council and the Danish Energy Research Program. The model provides an alternative approach to activity based travel demand analysis that excludes the time dimension. The approach may be thought of as an extension of the trip based frequency model and allows the model to deal with chains of tours and to treat the choice of activities as endogenous.

Neoclassical Versus Frontier Production Models? Testing for the Skewness of Regression Residuals

The empirical literature on production and cost functions is divided into two strands. The neoclassical approach concentrates on model parameters, while the frontier approach decomposes the disturbance term to a symmetric noise term and a positively skewed inefficiency term. We propose a theoretical justification for the skewness of the inefficiency term, arguing that this skewness is the key testable hypothesis of the frontier approach. We propose to test the regression residuals for skewness in order to distinguish the two competing approaches. Our test builds directly upon the asymmetry of regression residuals and does not require any prior distributional assumptions.

A Review of some Critical Assumptions in the Relationship between Economic Activity and Freight Transport

A number of conversion factors are often needed when projecting freight transport growth, depending on the level of detail of the projection. Here we investigate conversion factors that convert production in fixed prices in different industries into production of different commodities and further into weight terms. Data to describe these conversions are hard to come by and modellers have been left to resort to various ad hoc assumptions. We have obtained a data set covering the period from 1981 to 1992 detailing production by industry and commodity both in fixed prices and in tons based on the Danish national accounts. With these data we are able to check some of the assumptions that have commonly been made. Our findings thus have implications for future freight modelling exercises, in particular for what data it is necessary to collect and what relationships it is necessary to seek to model explicitly. We find that it is necessary to account for changing composition of production across industries, but that the commodity mix within each industry safely can be regarded as constant. Changing value densities account for almost a third of transport growth; however, this is attributable to the first year of data. Otherwise, value densities could be regarded as constant with our data. Finally, we find that using import or export data to impute value densities induces unacceptably large errors. (A)

Endogenous Scheduling Preferences and Congestion

We seek to better understand the scheduling of activities in time through a dynamic model of commuting with congestion, in which workers care solely about leisure and consumption. Implicit preferences for the timing of the commute form endogenously due to concave preferences and temporal agglomeration economies. Equilibrium exists uniquely and is indistinguishable from that of a generalized version of the classical Vickrey bottleneck model, based on exogenous trip-timing preferences; but optimal policies differ: the Vickrey model will under-predict the benefits of congestion pricing, and such pricing may make people better off even without considering the use of revenues.

Measuring Educational Heterogeneity And Labor Quality: A Note

This paper investigates the magnitude of the mismeasurement that occurs when only a few education categories are used in the construction of a constant quality index for labor input. By employing a very comprehensive data set it is found that the error resulting from the omission of information on education is relatively small. The empirical results are thus supportive of the current state of practice of constructing indices of constant quality labor input.

DECONVOLUTING PREFERENCES AND ERRORS: A MODEL FOR BINOMIAL PANEL DATA

In many stated choice experiments researchers observe the random variables V , X , and Y = 1{ U + δ ⊤ X + e null V }, t ≤ T , where δ is an unknown parameter and U and e null are unobservable random variables. We show that under weak assumptions the distributions of U and e null and also the unknown parameter δ can be consistently estimated using a sieved maximum likelihood estimation procedure.

ENDOGENOUS SCHEDULING PREFERENCES AND CONGESTION

We seek to better understand the scheduling of activities in time through a dynamic model of commuting with congestion, in which workers care solely about leisure and consumption. Implicit preferences for the timing of the commute form endogenously due to concave preferences and temporal agglomeration economies. Equilibrium exists uniquely and is indistinguishable from that of a generalized version of the classical Vickrey bottleneck model, based on exogenous trip-timing preferences; but optimal policies differ: the Vickrey model will under-predict the benefits of congestion pricing, and such pricing may make people better off even without considering the use of revenues.

Modelling the relation between income and commuting distance

We discuss the distribution of commuting distances and its relation to income. Using data from Denmark, the UK and the USA, we show that the commuting distance is (i) broadly distributed with a slow decaying tail that can be fitted by a power law with exponent γ ≈ 3 and (ii) an average growing slowly as a power law with an exponent less than one that depends on the country considered. The classical theory for job search is based on the idea that workers evaluate the wage of potential jobs as they arrive sequentially through time, and extending this model with space, we obtain predictions that are strongly contradicted by our empirical findings. We propose an alternative model that is based on the idea that workers evaluate potential jobs based on a quality aspect and that workers search for jobs sequentially across space. We also assume that the density of potential jobs depends on the skills of the worker and decreases with the wage. The predicted distribution of commuting distances decays as 1/r3 and is independent of the distribution of the quality of jobs. We find our alternative model to be in agreement with our data. This type of approach opens new perspectives for the modelling of mobility.

Mode choice endogeneity in value of travel time estimation

Abstract It is often found that the value of travel time (VTT) is higher for car drivers than for public transport passengers. This paper examines the possible explanation that the difference could be due to a selection effect. The result is an inability to measure the effect of a mode difference, e.g., comfort, among transport modes. We specify a model that captures the mode difference through a mode dummy and use econometric techniques that allow treatment of the mode dummy as the result of an individual choice and hence endogenous. Using first a standard logit model we find a large and significant difference between the VTT for bus and car. When we control for endogeneity using instruments, the mode dummy becomes smaller and just significant. Our investigation is novel in that it allows for endogeneity in the estimation of VTT but like other applications using instruments the results indicate that we have difficulty in finding good instrumental variables.