Suchergebnisse

Taxicabs are ubiquitous in cities throughout the world, and the industry is going through regulatory change with the growth of app-based services. In the United States, where taxicabs are typically regulated locally, licenses determine where taxis can pick up passengers. This means that for trips that end outside of licensed boundaries taxicabs are prohibited from picking up passengers and are forced to make "deadhead" return trips. This research estimates empty taxi travel associated with spatial restrictions on passenger trip origins in New York City. In 2012, New York introduced a special taxi category intended to improve taxi access in areas of the city considered underserved by taxicabs. The new green taxicabs, as they are called, can drop off passengers anywhere in the city but are restricted from picking up passengers in the central business districts and at any of the region's airports. Using detailed trip data for each taxi ride, we estimate that up to 500,000 kilometers per week of deadhead travel are associated with restrictions on pick up locations, and more than 20 percent of all green taxicab trips end in an area where the driver is prohibited from picking up a new passenger.

This paper distinguishes between the Private Finance Initiative (PFI) and the more general Public Private Partnerships (PPP). It traces the growth of the initiative since its start in 1992 to the current day and considers the implications of PFI for the public finances. A number of economic issues are discussed including bidding costs, financing costs and whole life costing. The importance of risk transfer in the value for money analysis of PFI projects is emphasised and the extent to which risk actually is transferred is questioned. Finally, the contribution of PFI towards modernising public service is recognised but the Audit Commission's recommendation that a wider range of procurement tools ought to be considered is noted.

The RESidual RADioactivity (RESRAD) computer code has been used for years to calculate carcinogenic risk and radiological dose from exposure to radionuclides. The basic ingestion, inhalation, and direct gamma intake equations used by RESRAD, Risk Assessment Guidance for Superfund (RAGS), and the Soil Screening Guidance for Radionuclides (SSG) are similar and can produce similar results, but there are some notable differences. Of particular interest is the fact that RESRAD incorporates sophisticated environmental transport models. Associated environmental parameters allow risk assessors to consider, among other variables, the size (i.e., surface area) of the contaminated zone, a variable not typically addressed quantitatively under the RAGS/SSG paradigm. Considering the similarities between basic RESRAD, RAGS, and SSG intake equations and given the broad acceptance of RESRAD, it stands to reason that RESRAD‐derived area factors may be used to supplement RAGS/SSG human health risk calculations. This would allow risk assessors to retrofit existing results or otherwise modify standard RAGS/SSG equations for use in site closeout planning under the Multi‐Agency Radiation Survey and Site Investigation Manual (MARSSIM), given a key component of the MARSSIM method is the consideration of small areas of elevated activity or "hot spots" through the use of area factors.