68,945 research outputs found

    Congestion costing critique

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    The Urban Mobility Report (UMR) is a widely-cited study that quantifies and monetises (measures in monetary units) traffic congestion costs in U.S. metropolitan regions. This report critically examines the UMR’s assumptions and methods. The UMR reflects an older planning paradigm which assumes that “transportation” means automobile travel, and so evaluates transport system performance based primarily on automobile travel speeds; it ignores other modes, other planning objectives and other impacts. The UMR methodology overestimates congestion costs and roadway expansion benefits by using higher baseline speeds and travel time unit cost values than most experts recommend, by ignoring induced travel impacts, and using an inaccurate speed-emission curve. Its estimates represent upper-bound values and are two- to four times higher than result from more realistic assumptions. The UMR claims that congestion costs are “massive,” although they increase total travel time and fuel consumption by 2% at most. It exaggerates future congestion problems by ignoring evidence of peaking vehicle travel and changing travel demands. The UMR ignores basic research principles: it fails to identify best current practices, explain assumptions, document sources, incorporate peer review, or respond to criticisms

    The restructuring and privatisation of British Rail: Was it really that bad?

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    This paper uses a social cost-benefit analysis (SCBA) framework to assess whether rail privatisation in Britain has produced savings in operating costs. The paper shows that major efficiencies have been achieved, consumers have benefited through lower prices, whilst the increased government subsidy has been largely recouped through privatisation proceeds. We also find that output quality is no lower (and is probably better) than under the counterfactual scenario of public ownership (pre-Hatfield). The achievement of further savings is key to delivering improved rail services in the future. This paper finds that a privatised structure, where shareholders demand a return on their investment, has led to significant improvements in operating efficiency - it remains to be seen whether the new regime, with a not-for-profit infrastructure owner, will deliver the same efficiency improvements

    Safe Routes to School: Helping Communities Save Lives and Dollars: 2011 Policy Report

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    Highlights the financial and health benefits of the federal program to improve safety for pedestrians and cyclists; promote healthy, active lifestyles for children; and improve environmental conditions near schools, as well as implementation issues

    Evaluation of Coordinated Ramp Metering (CRM) Implemented By Caltrans

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    Coordinated ramp metering (CRM) is a critical component of smart freeway corridors that rely on real-time traffic data from ramps and freeway mainline to improve decision-making by the motorists and Traffic Management Center (TMC) personnel. CRM uses an algorithm that considers real-time traffic volumes on freeway mainline and ramps and then adjusts the metering rates on the ramps accordingly for optimal flow along the entire corridor. Improving capacity through smart corridors is less costly and easier to deploy than freeway widening due to high costs associated with right-of-way acquisition and construction. Nevertheless, conversion to smart corridors still represents a sizable investment for public agencies. However, in the U.S. there have been limited evaluations of smart corridors in general, and CRM in particular, based on real operational data. This project examined the recent Smart Corridor implementation on Interstate 80 (I-80) in the Bay Area and State Route 99 (SR-99, SR99) in Sacramento based on travel time reliability measures, efficiency measures, and before-and-after safety evaluation using the Empirical Bayes (EB) approach. As such, this evaluation represents the most complete before-and-after evaluation of such systems. The reliability measures include buffer index, planning time, and measures from the literature that account for both the skew and width of the travel time distribution. For efficiency, the study estimates the ratio of vehicle miles traveled vs. vehicle hour traveled. The research contextualizes before-and-after comparisons for efficiency and reliability measures through similar measures from another corridor (i.e., the control corridor of I-280 in District 4 and I-5 in District 3) from the same region, which did not have CRM implemented. The results show there has been an improvement in freeway operation based on efficiency data. Post-CRM implementation, travel time reliability measures do not show a similar improvement. The report also provides a counterfactual estimate of expected crashes in the post-implementation period, which can be compared with the actual number of crashes in the “after” period to evaluate effectiveness

    iTETRIS: An Integrated Wireless and Traffic Platform for Real-Time Road Traffic Management Solutions

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    Wireless vehicular cooperative systems have been identified as an attractive solution to improve road traffic management, thereby contributing to the European goal of safer, cleaner, and more efficient and sustainable traffic solutions. V2V-V2I communication technologies can improve traffic management through real-time exchange of data among vehicles and with road infrastructure. It is also of great importance to investigate the adequate combination of V2V and V2I technologies to ensure the continuous and costefficient operation of traffic management solutions based on wireless vehicular cooperative solutions. However, to adequately design and optimize these communication protocols and analyze the potential of wireless vehicular cooperative systems to improve road traffic management, adequate testbeds and field operational tests need to be conducted. Despite the potential of Field Operational Tests to get the first insights into the benefits and problems faced in the development of wireless vehicular cooperative systems, there is yet the need to evaluate in the long term and large dimension the true potential benefits of wireless vehicular cooperative systems to improve traffic efficiency. To this aim, iTETRIS is devoted to the development of advanced tools coupling traffic and wireless communication simulators

    Long-term U.S transportation electricity use considering the effect of autonomous-vehicles: Estimates & policy observations

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    In this paper, we model three layers of transportation disruption – first electrification, then autonomy, and finally sharing and pooling – in order to project transportation electricity demand and greenhouse gas emissions in the United States to 2050. Using an expanded kaya identity framework, we model vehicle stock, energy intensity, and vehicle miles traveled, progressively considering the effects of each of these three disruptions. We find that electricity use from light duty vehicle transport will likely be in the 570–1140 TWh range, 13–26%, respectively, of total electricity demand in 2050. Depending on the pace at which the electric sector decarbonizes, this increase in electric demand could correspond to a decrease in LDV greenhouse gas emissions of up to 80%. In the near term, rapid and complete transport electrification with a carbon-free grid should remain the cornerstones of transport decarbonization policy. However, long-term policy should also aim to mitigate autonomous vehicles’ potential to increase driving mileage, urban and suburban sprawl, and traffic congestion while incentivizing potential energy efficiency improvements through both better system management and the lightweighting of an accident-free vehicle fleet

    Bumpy Roads Ahead: America's Roughest Rides and Strategies to Make our Roads Smoother

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    These days, potholes and pavement deterioration make it a challenge to keep the wheel steady on America's roads and highways. More than a quarter of the nation's major urban roadways -- highways and major streets that are the main routes for commuters and commerce -- are in poor condition. These critical links in the nation's transportation system carry 78 percent of the approximately 2 trillion miles driven annually in urban America. With state and local governments unable to adequately fund road repairs and with the current federal surface transportation program set to expire on September 30, 2014, road conditions could get even worse in the future. In this report, TRIP examines the condition of the nation's major urban roads, including pavement condition data for America's most populous urban areas, recent trends in travel, the latest developments in repairing roads and building them to last longer, and the funding levels needed to adequately address America's deteriorated roadways. For the purposes of this report, an urban area includes the major city in a region and its neighboring or surrounding suburban areas. Pavement condition data are the latest available and are derived from the Federal Highway Administration's (FHWA) 2011 annual survey of state transportation officials on the condition of major state and locally maintained roads and highways, based on a uniform pavement rating index. The pavement rating index measures the level of smoothness of pavement surfaces, supplying information on the ride quality provided by road and highway surfaces

    Understanding the role of performance targets in transport policy

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    The measurement of performance in the public sector has become increasingly important in recent years and it is now commonplace for transport organisations, and local and national governments, to publish performance goals for service supply and quality. Such commitments, when time referenced, are known as targets. This paper explain how changes in management style, consumer rights legislation, contractual obligations and other factors have combined to make management-by targets increasingly common in the public sector. The advantages and disadvantages of management-by-targets are illustrated through discussion of the processes and experience of setting transport targets in UK national transport policy. We conclude that while some of the targets have had a significant impact on policy makers, managers and their agents, the effects have not always been as intended

    Safe Routes to School 2009 Policy Report: Moving to the Future: Building on Early Achievements

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    This report gives background information on Safe Routes to School and details challenges and opportunities in program implementation. The 2009 Policy Report also discusses a number of "big-picture" policies and practices that affect -- positively or negatively -- the ability of children to walk and bicycle to school or that can help institutionalize SRTS programs in a larger context. Some of these policies include school siting, complete streets, and school bus route cuts
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