The Signs of the Times: Imposing a Globally Signed Condition on Willingness to Pay Distributions

A feature of recent developments in choice models that enable estimation of the distribution of willingness to pay (WTP) is that the sign of the distribution can change over the range. Behaviourally this often makes little sense for attributes such as travel time on non-discretionary travel, despite a growing recognition of positive utility over some travel time ranges. This can in part be attributed to the analytical distribution that is selected (except the cumbersome lognormal), many of which are unconstrained over the full range. Although a number of analysts have imposed constraints on various distributions for random parameters that can satisfy the single-sign condition, these restrictions are, with rare exception, only satisfied for the mean and the standard deviation estimates of a random parameter. When heterogeneity around the mean and/or heteroscedasticity around the standard deviation is allowed for, however, the constraint condition is often not satisfied. Given the popularity of distributions other than the lognormal, in order to satisfy the sign condition under the most general form of parameterisation, we need to impose a global sign condition. In this paper we show how this might be achieved in the context of the valuation of travel time savings for car commuters choosing amongst an offered set of route-specific travel times and costs. We illustrate the impact of the constraint under a globally constrained Rayleigh distribution for total travel time parameterisation, contrasting the evidence with a multinomial logit model and a range of other distributional assumptions within the mixed logit framework. Discussions with Bill Greene, John Rose, Ken Train and especially Juan de Dios Ortuzar have been invaluable as have the comments of referees.     

Modelling,simulation and evaluation of ground vibration caused by rail vehicles*

ABSTRACT

There is a great need to develop rail networks over long distances and within cities as more sustainable transport options. However, noise and vibration are seen as a negative environmental consequence. Compared with airborne noise, the related problem of ground vibration is much more complex. The properties of the ground vary significantly from one location to another. There is no common assessment criterion or measurement quantity and no equivalent to the noise maps. Ground-borne vibration is transmitted into buildings and perceived either as feelable whole-body vibration or as low frequency noise; it can also affect sensitive equipment but it is generally at a level that is too low to cause structural or cosmetic damage to buildings. A review is given of evaluation criteria for both feelable vibration and ground-borne noise, empirical and numerical prediction methods, the main vehicle and track parameters that can affect the vibration levels and a range of possible mitigation methods.     

Public access to ocean beaches: If you find a parking space,how do you get to the beach

The public presently owns, or has the right to use, a substantial portion of the nation's ocean beaches. However, the public cannot, in fact, use many of these beaches because there is no legal access to them. As the coast develops, more and more areas become closed to the public. The states are now being encouraged to plan for access to the beaches; there are a number of tools and techniques at their disposal.     

International private and public reinforcing dependencies for the innovation of automotive emission control systems in Japan and USA

In the beginning of the 1970s, the economies of USA and Japan were growing fast and environmental pollution was increasing to alarming levels. As passenger car emissions were found to be significant and rapidly increasing, their reduction was specially targeted. Following a bill passed by US Congress in 1968, requirements were set in 1970 for the vehicle manufacturers to reduce the emissions of carbon monoxide (CO) and hydrocarbons (HC) with 90% by 1975, and nitrogen oxides (NO_x) with 90% by 1976. These requirements were soon adapted to the Japanese regulatory framework, and were known in both countries as the “Muskie Act” or “Muskie Law” after the senator who developed the original bill.The new requirements spurred tremendous research and development efforts. Car manufacturers and research institutions in USA, Japan and Europe investigated and developed alternative solutions, including gas turbine and steam engine vehicles. California, the USA state with the most severe air quality problems and the only state at the time allowed to establish more strict requirements than federal regulation, established requirements implying the use of oxidation catalysts in 1975 and three-way catalysts (TWC’s) in 1977. Japan as a nation adopted similar requirements 1976 and 1978. Export of cars from Japan to USA increased rapidly. The rest of USA adopted emission standards similar to California’s only in 1981, timing USA vehicle sales rebound after the energy crisis and grave economic downturn. Strict requirements were thus established only after more than a decade of civic and legal processes between federal authorities, the car manufacturers and NGO’s.The history of vehicle development is one of cooperation and competition. This paper argues that the international cooperation on different levels of society (government, industry and science) together with commercial competition between the two countries was strong, continuous and instrumental in enabling the development of technology, appropriate regulation and infrastructural changes and thus created a market for cleaner cars and effectively reduced emissions from the growing vehicle fleet. In other words, the introduction of TWCs was reinforced by the simultaneous development of mitigating technology in two car producing countries competing for market space.     

Do public transport investments promote urban economic development? Evidence from bus rapid transit in Bogotá, Colombia

In 2000, the city of Bogotá, Colombia embarked on a grand land use and transportation system experiment. The transformation of Bogotá included building the TransMilenio Bus Rapid Transit (BRT) system, a city-wide system that offers speed and convenience similar to that of an underground metro. TransMilenio is widely regarded as a success, and cities around the world are planning or building similar systems. In this paper, we use a repeated cross-section labor market dataset to assess whether access to the new BRT system affects the incomes of those who live in station area neighborhoods. Our results indicate that the opening of the TransMilenio system was associated with increased income for those living near—but not immediately adjacent to—trunk line stations. This relationship is strongest in the lower and middle-income range. There are at least two possible explanations for this result: 1. existing residents earn higher wages, or 2. higher income workers move to the neighborhood. Our data do not allow us to distinguish clearly between them, but available evidence suggests that much of the effect is likely due to relocation. Our results stand in contrast to prior work, which has largely suggested that improvements in public transit will tend to reduce wages in station areas.     

The use of dynamic programming in optimally allocating funds for highway safety improvements

An integrated system approach to traffic accident countermeasure selection is presented. This approach draws primarily upon the resources of a computerized accident records system for identifying high accident locations. Once high accident locations are identified by type, local investigations of these locations are conducted producing standardized cost and benefit data. These data are processed through a dynamic programming algorithm to produce optimal policies for implementation. Since this system has been in operation in two states in the United States for about five years, it should be of special interest to practitioners.