17,755 research outputs found
Urban Transportation Policy: A Guide and Road Map
The main transportation issues facing cities today fall into familiar categories--congestion and public transit. For congestion, there is now a far richer menu of options that are understood, technically feasible, and perhaps politically feasible. One can now contemplate offering roads of different qualities and prices. Many selected road segments are now operated by the private sector. Road pricing is routinely considered in planning exercises, and field experiments have made it more familiar to urban voters. Concerns about environmental effects of urban trucking have resulted in serious interest in tolled truck-only express highways. As for public transit, there is a need for political mechanisms to allow each type of transit to specialize where it is strongest. The spread of ĂąâŹĆbus rapid transitù⏠has opened new possibilities for providing the advantages of rail transit at lower cost. The prospect of pricing and privatizing highway facilities could reduce the amount of subsidy needed to maintain a healthy transit system. Privately operated public transit is making a comeback in other parts of the world. The single most positive step toward better urban transportation would be to encourage the spread of road pricing. A second step, more speculative because it has not been researched, would be to use more environmentally-friendly road designs that provide needed capacity but at modest speeds, and that would not necessarily serve all vehicles.Transportation policy; Road pricing; Privatization; Product differentiation
Private Provision of Highways: Economic Issues
This paper reviews issues raised by the use of private firms to finance, build, and/or operate highways ĂąâŹâ issues including cost of capital, level and structure of tolls, and adaptability to unforeseen changes. The public sectorâs apparent advantage in cost of capital is at least partly illusory due to differences in tax liability and to constraints on the supply of public capital. The evidence for lower costs of construction or operation by private firms is slim. Private firms are likely to promote more efficient pricing. Effective private road provision depends on well-structured franchise agreements that allow pricing flexibility, restrain market power, enforce a sound debt structure, promote transparency, and foster other social goals.Privatization; Road finance; Toll road; Road pricing
Spatial Hedonics and the Willingness to Pay for Residential Amenities
Housing rents may be influenced by characteristics of nearby properties, an effect captured by spatial autoregression in a hedonic rent equation. We investigate the implications of spatial autoregression for measuring the marginal welfare effects due to a change in a residential amenity such as air quality. We show that if spatial price interdependence arises from technological spillovers, such that utility depends directly on neighboring property values, then the welfare change is given by the reduced form of the autoregressive model, effectively applying a "spatial multiplier" to the relevant implicit price. If instead spatial interdependence arises from merely pecuniary spillovers, as is commonly supposed in motivating spatial autoregression, then no spatial multiplier on implicit prices is called for in computing welfare; but it is then especially important to use the autoregressive model to measure those implicit prices.Spatial autocorrelation; spatial lag; welfare; willingness to pay; hedonic price function
Estimation of causal effects using instrumental variables with nonignorable missing covariates: Application to effect of type of delivery NICU on premature infants
Understanding how effective high-level NICUs (neonatal intensive care units
that have the capacity for sustained mechanical assisted ventilation and high
volume) are compared to low-level NICUs is important and valuable for both
individual mothers and for public policy decisions. The goal of this paper is
to estimate the effect on mortality of premature babies being delivered in a
high-level NICU vs. a low-level NICU through an observational study where there
are unmeasured confounders as well as nonignorable missing covariates. We
consider the use of excess travel time as an instrumental variable (IV) to
control for unmeasured confounders. In order for an IV to be valid, we must
condition on confounders of the IV---outcome relationship, for example, month
prenatal care started must be conditioned on for excess travel time to be a
valid IV. However, sometimes month prenatal care started is missing, and the
missingness may be nonignorable because it is related to the not fully measured
mother's/infant's risk of complications. We develop a method to estimate the
causal effect of a treatment using an IV when there are nonignorable missing
covariates as in our data, where we allow the missingness to depend on the
fully observed outcome as well as the partially observed compliance class,
which is a proxy for the unmeasured risk of complications. A simulation study
shows that under our nonignorable missingness assumption, the commonly used
estimation methods, complete-case analysis and multiple imputation by chained
equations assuming missingness at random, provide biased estimates, while our
method provides approximately unbiased estimates. We apply our method to the
NICU study and find evidence that high-level NICUs significantly reduce deaths
for babies of small gestational age, whereas for almost mature babies like 37
weeks, the level of NICUs makes little difference. A sensitivity analysis is
conducted to assess the sensitivity of our conclusions to key assumptions about
the missing covariates. The method we develop in this paper may be useful for
many observational studies facing similar issues of unmeasured confounders and
nonignorable missing data as ours.Comment: Published in at http://dx.doi.org/10.1214/13-AOAS699 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Should Urban Transit Subsidies Be Reduced?
This paper derives intuitive and empirically useful formulas for the optimal pricing of passenger transit and for the welfare effects of adjusting current fare subsidies, for peak and off-peak urban rail and bus systems. The formulas are implemented based on a detailed estimation of parameter values for the metropolitan areas of Washington (D.C.), Los Angeles, and London. Our analysis accounts for congestion, pollution, and accident externalities from automobiles and from transit vehicles; scale economies in transit supply; costs of accessing and waiting for transit service as well as service crowding costs; and agency adjustment of transit frequency, vehicle size, and route network to induced changes in demand for passenger miles. The results support the efficiency case for the large fare subsidies currently applying across mode, period, and city. In almost all cases, fare subsidies of 50% or more of operating costs are welfare improving at the margin, and this finding is robust to alternative assumptions and parameters.Transit subsidies; Scale economies; Traffic congestion; Welfare effects
Fuel Efficiency and Motor Vehicle Travel: The Declining Rebound Effect
We estimate the rebound effect for motor vehicles, by which improved fuel efficiency causes additional travel, using a pooled cross section of US states for 1966-2001. Our model accounts for endogenous changes in fuel efficiency, distinguishes between autocorrelation and lagged effects, includes a measure of the stringency of fuel-economy standards, and allows the rebound effect to vary with income, urbanization, and the fuel cost of driving. At sample averages of variables, our simultaneous-equations estimates of the short- and long-run rebound effect are 4.5% and 22.2%. But rising real income caused it to diminish substantially over the period, aided by falling fuel prices. With variables at 1997-2001 levels, our estimates are only 2.2% and 10.7%, considerably smaller than values typically assumed for policy analysis. With income at the 1997 â 2001 level and fuel prices at the sample average, the estimates are 3.1% and 15.3%, respectively.Carbon dioxide; Fuel economy; Travel demand; Motor vehicle use; Rebound effect
Applied Welfare Economics with Discrete Choice Models
Economists have been paying increasing attention to the study of situations in which consumers face a discrete rather than a continuous set of choices. Such models are potentially very important in evaluating the impact of government programs upon consumer welfare. But very little has been said in general regarding the tools of applied welfare economics indiscrete choice situations. This paper shows how the conventional methods of applied welfare economics can be modified to handle such cases. It focuses on the computation of the excess burden of taxation, and the evaluation of quality change. The results are applied to stochastic utility models, including the popular cases of probit and logit analysis. Throughout, the emphasis is on providing rigorous guidelines for carrying out applied work.
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