@article{ref1,
title="A statistical explanation for some of the effects of data aggregation on estimates on transport planning model parameters",
journal="Proceedings of the International Research Council on the Biomechanics of Injury conference",
year="1975",
author="Wright, C. C.",
volume="3",
number="",
pages="1-12",
abstract="This paper describes the physical problem, reviews the mathematical approach (trip generation models), and discusses the practical implications involved. The conditions required for household equations and zonal equations to be identical are detailed, and the characteristics are discussed of a linear regression model for household trip generation. The inter-relation of household trips (but not of trip rates or incomes) is described, and the details are given of household income and trip rate related through an intermediate variable. The effects of different levels of aggregation are discussed. The study concluded that zonal regression equations will differ from the corresponding household regression equations if the zone boundaries enclose area of roughly uniform housing and population characteristics. For the prediction of total trips arising from each zone at some future date, a household regression would be less accurate than one fitted to zonal means. Since category analysis methods are essentially household based, there must be similar reservations about their use for zonal prediction.<p />",
language="en",
issn="2235-3151",
doi="",
url="http://dx.doi.org/"
}