Maximizing Revenues for Online-Dial-a-Ride

In the classic Dial-a-Ride Problem, a server travels in some metric space to serve requests for rides. Each request has a source, destination, and release time. We study a variation of this problem where each request also has a revenue that is earned if the request is satisfied. The goal is to serve requests within a time limit such that the total revenue is maximized. We first prove that the version of this problem where edges in the input graph have varying weights is NP-complete. We also prove that no algorithm can be competitive for this problem. We therefore consider the version where edges in the graph have unit weight and develop a 2-competitive algorithm for this problem

The Political Economy of Cable - "Open Access."

Advocates of "open access" claim that Internet Service Providers (ISPs) should be able to use a cable TV system's bandwidth on the same terms offered to ISPs owned by the cable system. On that view, "open access" mitigates a monopoly bottleneck and encourages the growth of broadband. This paper shows that cable operators do enjoy market power, and do seek to leverage a dominant position in video into the broadband access market by allocating too little bandwidth for Internet access. Yet, rather than protect cable operators from cannibalizing their cable TV revenue, this strategy defends against imposition of common carrier regulation, which would allow system capacity to be appropriated by regulators and rival broadband networks. Ironically, the push for "open access" limits Internet access by encouraging this under-allocation of broadband spectrum, and by introducing coordination problems slowing technology deployment. These effects are empirically evident in the competitive superiority of cable's "closed" platform vis-a-vis "open" DSL networks, and in financial market reactions to key regulatory events and mergers in broadband.

Do You Know the Way to L.A.? San Jose Shows How to Turn an Urban Area into Los Angeles in Three Stressful Decades

California cities have the least affordable housing and the most congested traffic in the nation. California's housing crisis results directly from several little-known state institutions, including local agency formation commissions (LAFCos), which regulate annexations and the formation of new cities and service districts; the California Environmental Quality Act, which imposes high costs on new developments; and a 1971 state planning law that effectively entitles any resident in the state to a say in how property owners in the state use their land. Cities such as San Jose have manipulated these institutions and laws with the goal of maximizing their tax revenues. Meanwhile, California's transportation planning has allowed transit agencies, such as San Jose's Valley Transportation Authority and Los Angeles' Metropolitan Transportation Authority, to hijack tax revenues that were originally dedicated to highways so they can build rail empires that will do little or nothing to relieve congestion. New highway construction in the 1990s cut San Jose congestion in half, but congestion is again worsening as funds once spent on highways are now diverted to expensive and little-used rail transit projects. California should change its planning laws to forbid cities and counties from conspiring to drive up housing prices in order to maximize tax revenues. California and its urban areas should also fund transportation out of user fees instead of taxes, thus making transportation more responsive to the needs of users instead of politically powerful special interest groups. Other states should avoid passing laws that create similar conditions. These recommendations and eight others in this report will greatly improve the livability of San Jose and other California urban areas

Rural Transit in Oregon: Current and Future Needs

The purpose of the research reported was to identify the current status and needs for general public transportation in Oregon’s rural areas, as well as opportunities and barriers (e.g., funding, governance issues, and leadership) to expanding services over a 20 year period. Oregon is a largely rural state. This lack of density poses problems for the provision of public transit, whether through fixed route or demand response service. People living in the rural areas and who lack cars and access to public transportation are at a strong disadvantage. With no access to these transit resources, they may be limited to relying on friends, family, or associates for travel. This reliance may severely limit the flexibility of travel and limit those individuals’ independence. When transit is not available, older adults and people with disabilities, in particular, experience more restrictions on their ability to travel and must rely more heavily on informal networks or formal supportive services to meet their needs. Rural public transit also plays a vital role for agricultural workers. The lack of transit options in rural areas, therefore, leaves many rural citizens at a tremendous economic as well as social disadvantage. Improved rural transit service could enhance the quality of life for Oregon’s rural residents and contribute to the state’s economic well-being by facilitating travel to jobs and shops, access to medical services, volunteering, and other forms of participation in the community. The research reported here identifies the current status and needs for general public transportation in Oregon’s rural areas, as well as opportunities and barriers (e.g., funding, governance issues, and leadership) to expanding services over a 20 year period

On the inefficiency of ride-sourcing services towards urban congestion

The advent of shared-economy and smartphones made on-demand transportation services possible, which created additional opportunities, but also more complexity to urban mobility. Companies that offer these services are called Transportation Network Companies (TNCs) due to their internet-based nature. Although ride-sourcing is the most notorious service TNCs provide, little is known about to what degree its operations can interfere in traffic conditions, while replacing other transportation modes, or when a large number of idle vehicles is cruising for passengers. We experimentally analyze the efficiency of TNCs using taxi trip data from a Chinese megacity and a agent-based simulation with a trip-based MFD model for determining the speed. We investigate the effect of expanding fleet sizes for TNCs, passengers' inclination towards sharing rides, and strategies to alleviate urban congestion. We show that the lack of coordination of objectives between TNCs and society can create 37% longer travel times and significant congestion. Moreover, allowing shared rides is not capable of decreasing total distance traveled due to higher empty kilometers traveled. Elegant parking management strategies can prevent idle vehicles from cruising without assigned passengers and lower to 7% the impacts of the absence of coordination.Comment: Submitted to Transportation Research Part

Welfare consequences of request stops at transport services with low demand

Background: Demand-responsive transport is an alternative to fixed-route, fixed-scheduled transport services in low-demand areas. Objective: This paper discusses the welfare and distributional consequences of the implementation of request stops (RSs) on a scheduled fixed-stop transport service. Method: The discussion is based on a general welfare model. The focus is on discussing how the magnitudes of the welfare effects on different groups of travellers are influenced by travel patterns and the characteristics of the travellers involved. Results: The effects of implementing RSs are critically dependent on the booking procedure, the variation in demand throughout the day, and the travellers’ time values per hour when on the mode and when arriving at the destinations before having any appointments. Moreover, the benefits for the operators and the authorities depend strongly on the risk profile in the tendering contract.publishedVersio

Solutions for Impact Investors: From Strategy to Implementation

In writing this monograph, our main goal is to provide impact investors with tools to tighten the link between their investment decisions and impact creation. Our intent is threefold: to attract more capital to impact investing; to assist impact investors as they move from organizational change to executing and refining their impact investment decision-making process; and to narrow the gap within foundations between program professionals and investment professionals thereby contributing to a mutual understanding and implementation of a portfolio approach to impact investing.Additionally, we intend to help break down the barriers making it difficult to identify opportunities in impact investing. To this end, we provide examples throughout the monograph and at www.rockpa.org/impactinvesting of impact investment opportunities in most major asset classes.While we understand the important role that impact investors can play in providing financial capital, we also want to acknowledge the wide range of non-financial resources needed to address the world's problems. Our intent with this monograph is not to provide a comprehensive list of investments across asset classes nor any type of investment advice with regard to the selected profiles. We strongly encourage the reader to conduct their own assessment and evaluation for risk and suitability before considering any investment

Simulation approach for an integrated decision support system for demand responsive transport planning and operation

Rural areas are becoming more desert from day to day, leading to complex dispersed and scarce demand patterns for public transport. As a consequence, conventional transport services are becoming less frequent, reducing levels of service (e.g., low occupancy rates, usage of old vehicles). With rigid predefined routes and schedules, they are inappropriate to operate in such environments. Demand Responsive Transport (DRT) systems have been seen as an interesting alternative solution, providing flexible transport services to meet trip requests. This solution has already been adopted in several countries as a way to increase user’s mobility and mitigate social exclusion. There are however some issues concerning DRT scheme design and evaluation requiring further developments. Namely, there is still a lack of adequate tools to support some of the strategic and tactic level decisions that must be made at the design phase. In this research, we propose an Integrated Decision Support System (IDSS) and general action methodology that will allow achieving better planning decisions and allowing the evaluation of alternative scheme designs prior to its implementation. The IDSS and methodology are based on an event-driven simulation framework which emulates real-world customers’ behavior and vehicles movements. The paper will concentrate its analysis on this framework. An illustrative numerical experiment is presented and briefly discussed.The authors acknowledge the financial support provided by the European Union through FEDER - "Programa Operacional Factores de Competitividade" (POFC) and by the Portuguese Government through FCT - "Fundação para a Ciência e a Tecnologia". Research grants: FCT/TRA/72871-2006 and FCT/SEN-TRA/116216-2009