Ramp meters in the Twin Cities have been the subject of a recent test of their effectiveness, involving turning them off for eight weeks. This paper analyzes the results with and without ramp metering for several representative freeways during the afternoon peak period. Seven performance measures: mobility, equity, productivity, consumers’ surplus, accessibility, travel time variation and trave...

We consider a ridesharing problem where there is uncertainty about the completion of trips from both drivers and riders. Specifically, we study ridesharing mechanisms that aim to incentivize commuters to reveal their valuation for trips and their probability of undertaking their trips. Due to the interdependence created by the uncertainty on commuters’ valuations, we show that the Groves mechan...

BACKGROUND We used the introduction of free bus travel for young people in London in 2005 as a natural experiment with which to assess its effects on active travel, car use, road traffic injuries, assaults, and on one measure of social inclusion, total number of trips made. METHODS A controlled before-after analysis was conducted. We estimated trips by mode and distances travelled in the prei...

This article tackles the multi-trip vehicule routing problem with time windows and limited duration. A trip is a timed route such that a succession of trips can be assigned to one vehicle. We provide a two-phase exact algorithm to solve it. The first phase enumerates possible ordered lists of client matching trip maximum duration criterion. The second phase uses a Branch and Price scheme to gen...

Parasites, by altering the nutritional and energetic state of their hosts, can significantly alter their foraging behaviour. In honeybees, an infection with Nosema ceranae has been shown to lower the energetic state of individual bees, bringing about changes in behaviours associated with foraging. Comparing the foraging trip times, hive times in between trips, and the crop contents of uninfecte...

This paper presents the first approximation algorithms and the first inapproximability results for minmax path cover problems, where a capacity constraint restricts the number of customers that can be serviced by every trip of the paths in the cover. Depending on different applications, every path in the cover may either be restricted to contain only one trip, or be allowed to contain multiple ...

Penguins rely on vision to travel and hunt at sea. Vision in marine predators, particularly those hunting phototactic prey under a broad range of light intensities, must be better understood to realize how these species respond to changes in their environment. We studied the effects of daily cycles in light intensity on visual predators by examining the duration and timing of chinstrap penguins...

T he Agreement on Trade-Related Aspects of Intellectual Property Rights (the TRIPS Agreement, Box 1) has to a large extent harmonized standards for intellectual property rights, including patents. For many countries, the TRIPS standards were higher than their previous standards. For example, TRIPS obliges countries to allow patenting of pharmaceuticals and imposes a minimum duration of 20 years...