Safety Oriented Maneuvers for IVHS

The IVHS architecture of the California PATH program organizes traffic into platoons of closely spaced vehicles. Platoons are formed and broken up by two longitudinal control maneuvers, the merge and the split. A third longitudinal maneuver, decelerate to change lane, allows a platoon switching from one lane to another to enter its new lane at a safe spacing and speed. The maneuvers, particularly the merge, can be potentially hazardous. In a merge, the cars in the trail platoon are moving faster than those in the lead platoon, while the gap separating the two platoons is smaller than usual. A sudden deceleration by the lead platoon could cause a high-speed collision. If the relative velocities of the merging platoons can be constrained so that they are guaranteed never to collide at a high relative velocity, the merge can be considered safe. A maximum safe velocity for the trail platoon can be found for any given spacing and lead-platoon velocity. This paper presents a merge maneuver in which the velocity of the trail platoon never exceeds the maximum safe velocity. The controller switches among several feedback control laws that keep the velocity of the trail platoon inside a safe region and within comfort limits on jerk and acceleration, under normal circumstances. This merge maneuver can be considered to be the fastest merge strategy mat does not violate bounds on safety and comfort. The controller is also more robust to changes in the vehicles' acceleration capability than those that use a desired open-loop trajectory

The control approach used for the merge maneuver can be applied to the other maneuvers to ensure that they never result in a collision. The switching controllers for the split and decelerate to change lane maneuvers that are safe and yield a more comfortable ride than those that track a timed trajectory are also presented.     

ICT and road transportation safety in the United States: a case of “American exceptionalism”

This paper examines American attitudes about the role and structure of government and how those attitudes affect the safety potential of ICT-based road safety technologies. It examines these attitudes in the context of 3 current intelligent transportation systems (ITS) initiatives: IntelliDrive^SM, active traffic management (ATM), and automated enforcement. It concludes that cultural attitudes have a strong influence on the acceptance of such systems, and provides suggestions for how such systems might be implemented successfully.     

New routes on old railways: increasing rail’s mode share within the constraints of the existing railway network

This paper describes an integrated methodology for identifying potential ‘quick wins’ for mode shift from road to passenger rail transport. Firstly, a procedure for analysing rail’s relative competitiveness in the market for passenger transport between large urban areas is developed and then applied to a UK case study. The purpose of such analysis is to allow the identification of flows where rail is currently relatively uncompetitive (in terms of journey time in particular) and to assess the reasons for this poor performance, so that the issues which suppress rail use may be addressed. In parallel, a framework, methodology and tool for the assessment of existing and potential capacity (trains, seats, TEUs, etc.) is developed for both passenger and freight traffic, to identify and address network constraints. An illustrative example of the use of these demand and capacity assessment tools is then presented, with the tools used to identify and evaluate flows where rail demand is suppressed by poor service quality and where spare capacity exists which would allow the passenger rail service to be improved without requiring significant investments in infrastructure. The effects of such improvements on demand are predicted, and the cost implications of operating such additional services are discussed. The analysis suggests that there may be significant potential for increasing rail’s mode share by providing additional inter-urban services where rail currently offers an inferior service.     

Appraisal of rail investment projects: recent British experience

There has long been conflict over the degree to which railways should follow commercial or social investment criteria. This paper outlines the components of a comprehensive social cost‐benefit analysis of railway investment, and then describes the current approach in Britain. British Rail investment proposals are subject to a purely financial appraisal, although in the subsidized sectors of the railway this is subject to the proviso that a ‘broadly comparable’ level of service should be maintained. Local authorities and private operators are able to apply for a central government grant towards the cost of schemes they sponsor. But grant is only payable in respect of external benefits—that is, benefits other than to public transport users. Sponsors are also expected to seek contributions from private developers wherever possible. The difficulties to which this approach leads are discussed, and illustrated with two case studies of actual schemes. In one, it appears that failing to consider disbenefits to bus operators (and in turn to users of bus services) could lead to investments being undertaken which are not justified. In the other, a scheme which yields a high Net Present Value could not go ahead, in the form that we evaluated, because there is no way of recouping enough of the user benefits as revenue. Both are examples of the sort of distorting effect on decision‐making the current regime may have.     

On cost-efficiency of the global container shipping network

This paper presents a simple formulation in the form of a pipe network for modelling the global container-shipping network. The cost-efficiency and movement-patterns of the current container-shipping network have been investigated using heuristic methods. The model is able to reproduce the overall incomes, costs, and container movement patterns for the industry as well as for the individual shipping lines and ports. It was found that the cost of repositioning empties is 27% of the total world fleet running cost and that overcapacity continues to be a problem. The model is computationally efficient. Implemented in the Java language, it takes one minute to run a full-scale network on a Pentium IV computer.     

The Market for Transportation-Land Use Integration: Do Developers Want Smarter Growth than Regulations Allow?

Transportation and land use research of the past decade has focused in large part on the question of whether manipulating land uses in the direction of smart growth alternatives can reduce vehicle miles traveled (VMT) or otherwise improve travel behavior. Yet the notion of manipulating land uses implies that the alternative is somehow self-organized or market-based. This view appears to underestimate the extent to which current planning interventions in the United States – largely focused on lowering development densities, mandating ample road and parking designs, and separating land uses – impose an auto-oriented template on most new development. Rather than a market failure, the paucity of smart growth alternatives may be a planning failure – the result of municipal regulatory exclusion. This problem definition would shift the burden of proof for policy reform, as uncertainty in travel-behavior benefits would hardly justify the continuation of exclusionary regulations. If municipal regulations in fact constrain alternatives to low-density, auto-oriented development, one would expect developers to perceive unsatisfied market interest in such development. This article studies, through a national survey (676 respondents), US developers' perceptions of the market for pedestrian-and transit-oriented development forms. Overall, respondents perceive considerable market interest in alternative development forms, but believe that there is inadequate supply of such alternatives relative to market demand. Developer-respondents attribute this gap between supply and demand principally to local government regulation. When asked how the relaxation of these regulations would affect their product, majorities of developers indicated that such liberalization would lead them to develop in a denser and more mixed-use fashion, particularly in close-in suburban locales. Results are interpreted in favor land-policy reform based on the expansion of choice in transportation and land use. This view contrasts with a more prevalent approach which conditions policy interventions on scientific evidence of travel-behavior modification.     

An assessment of cost management regimes in British rail infrastructure provision

Over the last decade, British railway engineering efficiency has come under close scrutiny, with general perceptions of massive maintenance cost escalations and a general lack of control over these costs. This is exemplified by headline figures such as Roger Ford??s perceptions of a 50% rise in maintenance costs since privatisation (Mod Railw 638:8, 2001), or the more recent figure of a doubling in all rail costs since privatisation presented by Shaoul (Public Money Manag 26:151?C158, 2006). Little, however, has appeared in the academic literature on the subject. This paper considers these issues through an examination of British railway infrastructure costs over the period 1980?C2009, which has seen three different infrastructure management regimes in place??the nationalised BR (1980?C1994), the privatised Railtrack (1995?C2001) and the not for dividend Network Rail (2002?C2010). Infrastructure costs are examined in total for all operating costs (including maintenance but excluding renewals and depreciation), and under two sub categories, signalling and management costs. The results show that in the case of total operating costs, by the end of the period (up to 2010) these had returned to pre-privatisation levels. The results also show that costs increased significantly following privatisation due to imperfect competition in sub contractor markets, but large declines in the last 6?years have eradicated most of these costs increases, although still do not match the best achieved under full public sector management. Management costs associated with the infrastructure on the other hand have increased significantly.     

Organisation form,scale effects and efficiency in the British bus industry

The British bus industry is examined in light of fundamental reform in ownership and regulation. The industry is divided between privately and publicly owned companies, with the private sector further split between publicly listed owned subsidiaries and private limited companies. The change in ownership structure since privatization is analysed, and Data Envelopment Analysis used to estimate the extent of returns to scale and technical efficiency, as defined by one output and three inputs. Technical efficiency is further divided into managerial and organisational components, and comparisons made of median efficiency levels using a Mann Whitney statistical test.Increasing returns to scale are found for smaller companies, but the size of such returns varies with the company type. A minimum efficiency scale is identified, with constant returns above this point. A high degree of technical inefficiency is found to be present in the industry, which may initially suggest a lack of competition and reflect the oligopolistic structure that has emerged since privatisation. Privately owned companies are identified as more technically efficient, however this is due to significantly less organisational constraints, and considerable managerial inefficiency exists in this group. It is finally concluded that the high level of inefficiency may not reflect ownership, but rather industry characteristics, and rather than a lack of competition may be indicative of wasteful competition. It is suggested therefore there may be a need to make the market contestable rather than openly competitive.     

Boarding and alighting times for elderly persons using special bus service

This technical note examines the boarding and alighting times for elderly persons with respect to buses. The study was conducted with the assistance of Special Transport Service, a small-scale operation consisting of two buses. The main findings of the research are estimates for the boarding and alighting times for one ambulatory person: 2.328 minutes for boarding the bus and 1.002 minutes for alighting from the bus.     

Child pedestrian fatalities: The size of the problem and some suggested countermeasures

The child pedestrian death rates, per 100,000 population, for the USA and 22 European countries are compared. The safety measures used in some of these countries, for the two key areas of danger for children, the school journey and the residential environment, are outlined. Problems that might prevent the introduction of these countermeasures in some other countries are discussed. It is recommended that: 1) there should be special low speed limits on the roads outside all schools. On minor roads traffic calming measures would be suitable, on main roads new speed limits could be introduced and enforced by police surveillance using video camera techniques. 2) In suitable residential areas children should be enabled to play out in safety on the streets near their homes. In some countries the most acceptable way of achieving this might be by a change in the law whereby children would have priority in these designated Home Zones.