Accessibility is increasingly used as a metric when evaluating changes to public transport systems. Transit travel times contain variation depending on when one departs relative to when a transit vehicle arrives, and how well transfers are coordinated given a particular timetable. In addition, there is necessarily uncertainty in the value of the accessibility metric during sketch planning processes, due to scenarios which are underspecified because detailed schedule information is not yet available. This article presents a method to extend the concept of "reliable" accessibility to transit to address the first issue, and create confidence intervals and hypothesis tests to address the second.

Evidence-based transit and land use sketch planning using interactive accessibility methods on combined schedule and headwaybased networks.

The outer suburbs of Paris are home to a large number of low-income households driven from the centre by the workings of the property market. This shift could give rise to a new form of socio-spatial segregation insofar as the elevated costs of mobility in such highly car-dependent areas restrict and change these households' mobility patterns. These effects were observed in data on three groups of working people from the 2001 global transport survey. However, the socio-spatial impact of this outward movement is significantly reduced by the residential mobility of low-income households, which move from the most car-dependent areas to denser areas with better public transport provision. The presence of social housing in these areas only partially explains these migrations. These results obtained from 1999 census micro-data cast doubt upon the emergence of a new form of segregation in the outer suburbs described by Dodson and Sipe. of transport are less numerous. In these areas, the car has a radical monopoly in the sense proposed by Illich (1974)-it detracts from other means of transport, specifically by offering greater speed of travel and a high degree of flexibility. Urban outskirts are dependent on the car; this is the logical outcome of a period in which the trend was essentially to promote car use (Giuliano and Narayan, 2003).

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In cooperation with the Oregon Department of Transportation (ODOT) and other regional partners, the Portland regional intelligent transportation systems (ITSs) data archive was recently inaugurated via a direct fiber-optic connection between ODOT and Portland State University (PSU). In July 2004, the Portland Regional Transportation Archive Listing was activated; it received 20-s data from the 436 inductive loop detectors composing the Portland area's advanced traffic management system. PSU is designated as the region's official data archiving entity, consistent with the ITS architecture being developed. This paper discusses the steps taken for successful implementation of the Portland region's functional ITS data archive and plans for development and expansion. Included is a discussion of the archive structure, data storage, data processing, and user interface. An experiment involving Metro, the Portland region's metropolitan planning organization, demonstrates that archived loop detector data can be used to improve travel demand forecasts for the Portland region. The data archive will expand to include transit data, freeway incident data, city traffic signal data, and truck weigh-in-motion data.