bluuebunny/crossref_metadata_2025 huggingface dataset:
Fishery biology of the swordfish (Xiphias gladius, Linnaeus 1758) caught by surface longliners based in Itajaí, southern Brazil
Authors: Quaggio Ana Lia Campos , Lessa Rosângela P. T. , Kotas Jorge Eduardo , Lin Celson F.
Published: March 2014

The Xiphias gladius (Linnaeus, 1758) data used in the present study were obtained from commercial fishing cruises of the pelagic longline fleet based in Itajaí, operating in the Southwest Atlantic. For the Covariance models, fishing effort (number of hooks) and catches (kg) were pooled and categorized into the following groups: (1) year (1997, 1998, 2001, 2002 and 2007); (2) lunar phase; and (3) seasons, fishing effort being the covariate. The highest mean swordfish catch (kg) occurred during the waxing crescent moon and during wintertime. The Mantel-Haenszel procedure was applied to compare the efficiency of the two hooks tested, and showed that the "J" hook type (J 9/0 10º offset), traditionally used by the fleet, catches 1.2-fold more Xiphias gladius than the circle hook (18/0 10º offset), used as an optional device to reduce sea turtle bycatch. The conversion of individual dressed weight (kg) into total length (cm) from 2000 to 2002, showed that sub-adults represented 66% of the total catch.
National Geographic: understand civil engineering differently
Authors: Murray Mike , Ross Stuart
Published: March 2014

Undergraduate civil engineering students have access to a rich and diverse bank of textual and graphic knowledge concerning their chosen profession. However, over a number of decades, commentators have raised concerns that students have insufficient understanding of the role of civil engineering in society. Indeed, the call for universities to educate ‘global engineers’ emphasises the need for students to be schooled in the humanities, in parallel with their core computational studies. Unfortunately, engineering students in particular are not accustomed to regular exploratory reading. This paper considers the use of the National Geographic magazine as a means to ignite students' curiosity in the world around them. The results from a pilot study and a content analysis of a number of editions from over a decade show that this periodical regularly carries themes directly concerning the impact of civil engineering in society, be it political, financial, environmental, social or ecological.
Climate change impacts on connectivity in the ocean: Implications for conservation
Authors: Gerber Leah R. , Mancha-Cisneros Maria Del Mar , O'Connor Mary I. , Selig Elizabeth R.
Published: March 2014

Effective spatial management in the ocean requires a network of conservation areas that are connected by larval and adult dispersal. We propose a conceptual framework for including the likely impacts of a changing climate on marine connectivity, and synthesize information on the relationships between changing ocean temperature and acidification, connectivity and conservation tools. Our framework relies on concepts of functional connectivity, which depends on an organism's biological and behavioral responses to the physical environment, and structural connectivity, which describes changes in the physical and spatial structure of the environment that affect connectivity and movement. Our review confirms that ocean climate change likely reduces potential dispersal distance and therefore functional connectivity. Structural connectivity in the ocean will inevitably change with the spatial arrangement of biogenic habitats resulting from disturbance as well as enhanced growth and mortality due to climate change. Climate change will also likely reduce the spatial scale of connectivity, suggesting that we will need more closely spaced protected areas.
Changing tree composition by life history strategy in a grassland‐forest landscape
Authors: Hanberry Brice B. , Kabrick John M. , He Hong S.
Published: March 2014

After rapid deforestation in the eastern United States, which generally occurred during the period of 1850–1920, forests did not return to historical composition and structure. We examined forest compositional change and then considered how historical land use and current land use may influence forests in a grassland‐forest landscape, the Missouri Plains, where frequent surface fire was the historical land use and intensive agricultural is the current land use. We compared composition, distribution, and environmental relationships during historical (1813–1860) and current (2004–2008) forest surveys. We also examined changing composition of life history strategies of (1) stress tolerators based on fire tolerance, (2) colonizers based on shade intolerance, and (3) competitors based on shade tolerance. Open forest ecosystems of fire‐tolerant oaks have been replaced by forests of fire‐sensitive species, such as ashes, hackberry, and maples that expanded from riparian firebreaks and osage‐orange and eastern redcedar that expanded from planted windbreaks and rocky firebreaks. Colonizing species increased from 7% to 32% of total composition, with assisted tree migration from planting; we expect continued expansion particularly by eastern redcedar into areas unoccupied by trees. Competitive species have increased slightly to 38% of total composition although the trajectory of current forests suggested competitors may increase to 56% of total composition by replacing oaks in forest ecosystems. Changed success of life history strategies in an agricultural landscape without fire resulted in increased composition and extent of fire‐sensitive colonizers compared to fire‐tolerant oaks. We suggest that patterns of loss of fire‐tolerant oaks and increased distribution of fire‐sensitive species reflect suppression of fire, the historical land use. In addition, we suggest that subsequent land use dictates the success of either shade‐intolerant colonizers or shade‐tolerant competitors in current forests. Forests will be composed of shade‐intolerant colonizers where land use disturbance is frequent, such as in agricultural landscapes, and forests will be composed of species with greater shade tolerance where land use disturbance is less frequent.
Perceptions of Farmers' and Farmworkers' Wives on the Use and Hazards of Agrochemicals in Rural Vellore
Authors: Francis Mark Rohit , Raja Leeberk , Inbarani Esther , Regi Harsh , Nicolas Joel , Paul Nitin , Thomas Rohan , Earnest Philip , Kiran Ravi , War Shaniah , Alex Reginald , Balraj Vinohar , Mohan Venkata
Published: March 2014

Poor handling, storage, and application of agrochemicals have resulted in a steep rise in mortality and morbidity associated with their use. This study aimed at assessing the awareness of wives of farmers and farmworkers in rural Vellore on the use and health effects of agrochemicals to identify gaps in their knowledge. A cross-sectional survey among 512 wives was conducted. Nearly 75 percent of the wives (384/512) did not know that agrochemicals could pass through skin. Also, wives who owned between 1 and 5 acres of land had a higher odds of knowing that agrochemicals were harmful (OR: 1.71(1.03-2-85), p < 0.05) and need to be disposed safely (OR: 4.76 (1.47-15.36), p < 0.05), than those owning less than an acre or no land. There is a need to educate women associated with agriculture in India on the harms and proper use of agrochemicals in order to better protect and inform their households and communities.
Do You Get What You Measure? Research Opportunities Based on the Veterans Health Administration Experience
Authors: Thibodeau Nicole , Evans John Harry , Nagarajan Nandu J.
Published: March 2014

SYNOPSIS

Starting in 1995, the Veterans Health Administration (VHA) transformed a bureaucratic healthcare system into a performance-driven, patient-focused integrated healthcare network. The VHA's experience may offer lessons for private and public sector providers as the U.S. explores alternative healthcare delivery systems and payment methods. Similar patient-focused integrated systems are one of the hallmarks of the latest U.S. attempt to improve the quality and efficiency of healthcare delivery. The use of performance incentives to promote cooperation and innovation is also central to both the VHA and the U.S. reform. This study reviews the VHA's experience with an eye to identifying issues and potential research avenues for accounting researchers interested in the role of accounting information for control, coordination, and organizational change.
Optical optimization of organic solar cell with bulk heterojunction
Authors: Gondek E.
Published: March 2014

The work is devoted to the optimization of layer thickness in an organic photovoltaic cell. It presents the applied calculation method which is based on the optical transfer matrix 2×2 formalism. We present the influence of thickness of a PEDOT:PSS layer and of an active layer on the normalized modulus squared of optical electric fields distribution inside devices and on the distributions of exciton generation rate. We present the relationship between optimal thicknesses of the PEDOT:PSS layer and the active layer. We also present the influence of antireflection coating on distributions of optical electrical fields, as well as the distributions of exciton generation rate. Perpendicular and oblique illumination of the photovoltaic structure is discussed.
Interstitial pneumonitis after acetylene welding: A case report
Authors: Brvar Miran
Published: March 2014

Acetylene is a colorless gas commonly used for welding. It acts mainly as a simple asphyxiant. In this paper, however, we present a patient who developed a severe interstitial pneumonitis after acetylene exposure during aluminum welding. A 44-year old man was welding with acetylene, argon and aluminum electrode sticks in a non-ventilated aluminum tank for 2 h. Four hours after welding dyspnea appeared and 22 h later he was admitted at the Emergency Department due to severe respiratory insufficiency with pO2 = 6.7 kPa. Chest X-ray showed diffuse interstitial infiltration. Pulmonary function and gas diffusion tests revealed a severe restriction (55% of predictive volume) and impaired diffusion capacity (47% of predicted capacity). Toxic interstitial pneumonitis was diagnosed and high-dose systemic corticosteroid methylprednisolone and inhalatory corticosteroid fluticasone therapy was started. Computed Tomography (CT) of the lungs showed a diffuse patchy ground-glass opacity with no signs of small airway disease associated with interstitial pneumonitis. Corticosteroid therapy was continued for the next 8 weeks gradually reducing the doses. The patient’s follow-up did not show any deterioration of respiratory function. In conclusion, acetylene welding might result in severe toxic interstitial pneumonitis that improves after an early systemic and inhalatory corticosteroid therapy.
Laboratory diagnosis of paediatric tuberculosis in the European Union/European Economic Area: analysis of routine laboratory data, 2007 to 2011
Authors: Sanchini A , Fiebig L , Drobniewski F , Haas W , Richter E , Katalinic-Jankovic V , Pimkina E , Skenders G , Cirillo D M ,   European Reference Laboratory Network for TB (ERLN-TB), Balabanova Y
Published: March 2014

Laboratory confirmation of paediatric tuberculosis (TB) is frequently lacking. We reviewed the range of routine laboratory tests and their performance in different biological samples used to diagnose active TB in children. A questionnaire-based survey was conducted among the European Reference Laboratory Network for TB followed by collection of routine laboratory data on 10,549 paediatric samples tested in 2007 to 2011 at six reference laboratories (in Croatia, Germany, Italy, Latvia, Lithuania and the United Kingdom (UK)). The questionnaire showed that all laboratories used rapid assays. Non-respiratory samples were collected more often in Germany (135/275, 49.1%) and the UK (490/2,140, 22.9%) compared with Croatia (138/2,792, 4.9%), Latvia (222/2,401, 9.2%) and Lithuania (76/1,549, 4.9%). Overall laboratory positivity rates (isolation of Mycobacterium tuberculosis complex and/or identification of its nucleic acids in a sample) were higher in lymph node and gastric aspirate samples (14/203 (6.9%) and 43/1,231 (3.5%)) than in sputum samples (89/4,684 (1.9%)). Pooled sensitivity, specificity, positive and negative predictive values and accuracy of molecular assays assessed against solid or liquid culture were 79.2%, 93.6%, 67.1%, 96.5% and 91.6%, respectively. A more intensive approach in obtaining gastric aspirate and non-respiratory samples may increase laboratory confirmation of paediatric TB. Major effort is needed in optimisation and validation of molecular tests in these samples.
Operations of a Taxi Fleet for Advance Reservations Using Electric Vehicles and Charging Stations
Authors: Wang Hao , Cheu Ruey Long
Published: March 2014

This research investigated the operations of a taxi fleet that uses electric vehicles to accommodate only those trips for which advance reservations are made. In such operations, a dispatch system chains multiple trips to form a route and offers the route to a taxi driver. This unique problem is known as the Singapore taxi advance reservation with electric vehicles problem. Because electric vehicles have a limited running time before recharging is needed, the problem of minimizing the number of taxis used is formulated as a customized paired pickup and delivery problem with a time window and a charging station. A two-phase heuristic approach was proposed for solving this problem. Numerical experiments compared three solutions (nearest neighbor, sweep, and earliest time insertion heuristics), the effect of various battery recharging plans, and the effect of various numbers of charging stations for a simulated central business district network in Singapore. The results showed that (a) the earliest time insertion heuristic produced the best initial solutions; (b) as the maximum running time before recharging increased, the size of the fleet used decreased and there were fewer visits to the charging station, longer running times per taxi, and higher average revenues per driver; and (c) changing the number of charging stations had little effect on the system's performance measures.
Improving Rail Station Access with Feeder Bus Network Optimization and Mode Shifts
Authors: Huang Zhaodong , Liu Rongfang (Rachel)
Published: March 2014

Because of financial constraints, many transit agencies are trying to balance their budgets and provide an efficient transit network and services. This paper presents an improved model for feeder bus network development problems. The proposed approach consists of three main components: (a) an initial solution generation procedure, (b) a network features determination procedure, and (c) a solution search procedure. The tabu search is used as a metaheuristic method in the solution search procedure to find an optimal solution according to a given set of feasible solutions. The input for the new feeder bus network development problem includes the street network, demands from origins to the suburban rail station, and related parameters. The output demonstrates an optimized feeder bus network system and service frequencies for each route. The results show that the proposed method can be used by transit planners to optimize feeder bus systems that provide access to rail stations and other activity centers.
Simulation-Based Planning Framework for Choosing Where to Implement Bus Signal Priority in Mixed-Mode Operations
Authors: Shourijeh Morteza Tabatabaie , Faghri Ardeshir , Stevanovic Aleksandar
Published: March 2014

Planning is the first phase in a systematic approach toward better implementation of the bus signal priority (BSP) strategy and is required by the U.S. Department of Transportation as the first step of a standard system engineering approach for any federally funded intelligent transportation system project. Numerous studies have focused on various aspects of BSP design and operation; however, less attention has been paid to the planning phase of a BSP project. This study concentrated on planning for a BSP implementation project. The proposed framework is a heuristic approach to the combinatorial problem and is based on microsimulation; it requires a basic concept design for the BSP system, which is in planning. This concept design should be available from the planning steps that precede the choice of intersections to be equipped. The framework evaluated various scenarios for BSP at individual intersections by considering their marginal impact on the entire network and on the intersection. The intersection-level scenarios that resulted in the maximum total marginal improvement were selected for BSP implementation. The final output of the framework provided information on the intersections that should be equipped with BSP and the bus lines that were eligible to receive this priority at each intersection. The proposed framework was demonstrated in the network of downtown Dover, Delaware. An 18% savings in network average bus delay and no significant disbenefit to automobile traffic were achieved. The benefits translated into minimum savings of about $0.25 million a year through implementation of this framework during a peak traffic hour.
Designing Bus Rapid Transit Facilities for Constrained Urban Arterials
Authors: Beaton Eric B. , Bialostozky Evan , Ernhofer Oliver , Orosz Theodore V. , Reiss Taylor , Yuratovac Donald
Published: March 2014

Providing bus rapid transit (BRT) service on urban arterials can be a challenge for transportation agencies as they try to provide transit benefits within an existing street infrastructure. Projects must deliver high-quality transit service while supporting other needs, such as pedestrian activity, traffic flow, on-street parking, and crash safety. Transportation agencies must make trade-offs in designs to achieve a project's goals without miring the early project planning in costs and delays. This paper describes the selection by the New York City Department of Transportation and the Metropolitan Transportation Authority New York City Transit of the most appropriate on-street BRT running way design for Webster Avenue (US-1), a key north–south arterial in the central Bronx. The selection was based on a balanced, multimodal set of criteria. Three BRT running way alternatives—curbside, offset, and median bus lanes—were considered for Webster Avenue's 70-ft-wide right-of-way during the screening process. The four primary screening categories were transit operations, traffic operations, on-street parking and delivery curb space supply, and pedestrian benefits. Each design alternative was evaluated at two sample intersections that represented typical corridor conditions, and the results were expanded for a complete corridor evaluation. The evaluation found that the offset bus lane most effectively balanced the transit and traffic needs along the Webster Avenue corridor while maintaining on-street parking and supporting pedestrian activity; thus, it is the preferred corridor design.
Benefits to the Academic Community of Standardization of Bus Transit Automatic Vehicle Location Data
Authors: Robinson Steve
Published: March 2014

Automatic vehicle location (AVL) systems offer transit agencies and the academic community vast quantities of data on the operation of bus transit networks. However, turning this raw data into useful metrics that are of interest can be cumbersome and requires a significant amount of processing of AV L log files. Both transit agencies and the academic community would benefit if the AV L system output such metrics in a standardized format. This paper summarizes existing data exchange standards used in the bus transit industry and explains their benefits. A recent project undertaken by London Buses to analyze dwell time data is described, and the difficulties and costs involved in collecting the basic data required for analysis are highlighted. The paper proposes that more data standards should be defined for data output by AV L systems. If these standards were then implemented by AV L vendors, transit agencies and academics could get easy access to useful information that otherwise would require much time and cost to obtain.
Measuring Bus Stop Dwell Time and Time Lost Serving Stop with London iBus Automatic Vehicle Location Data
Authors: Robinson Steve
Published: March 2014

There is considerable research in the literature on the dwell time of buses at bus stops. However, common measures of dwell time do not consider the time lost by the bus decelerating and accelerating from a stationary speed to serve the stop. This paper identifies eight features that are observed when a bus serves a bus stop. These features were used to propose a definition of dwell time that can be measured with bus automatic vehicle location systems. A proposed metric gives the time that would have been saved had the bus stop not been present in the road network. Metrics were calculated for all bus stops on Route 45 in London; more than 50,000 stop visit events were used for the calculation. The time lost arriving at (i.e., decelerating) and departing from (i.e., accelerating) the bus stop was typically 11.6 s. This interval was often much longer than the time lost when the doors were open at the bus stop. Buses were shown to lose significant time serving a bus stop even if the bus never came to a halt at the stop. The method proposed in this paper can be used by transit agencies to measure the actual drive time of buses, removing the component of time lost serving the bus stop. The method can be used to identify bus stops that may need redesign to reduce the time lost in arriving and departing. A novel contribution of this research is that all proposed metrics can be automatically measured with modern automatic vehicle location systems, allowing easy collection of information.
Dynamic Holding Strategy to Prevent Buses from Bunching
Authors: Ji Yuxiong , Zhang H. Michael
Published: March 2014

This study proposed a robust dynamic control strategy to regulate bus headways and prevent buses from bunching by holding them at bus stops. The proposed strategy monitors bus locations in real time and estimates the time gaps between consecutive buses at a desired frequency. The holding times of all buses at their respective immediately downstream stops are determined simultaneously on the basis of the estimated time gaps. A procedure that consists of a discrete quadratic dynamic control program and a quadratic static optimization program was developed to produce a unique dynamic control law of holding times. Numerical investigations on an operational bus route revealed that the proposed strategy produced greater system reliability than did some existing control strategies and that the bus system under the control of the proposed strategy recovered promptly from large system disruptions.
Impact of Concessionary Bus Travel on the Well-Being of Older and Disabled People
Authors: Mackett Roger
Published: March 2014

This study examined the impact of the concessionary bus pass scheme for older and disabled people in Great Britain. The scheme offers people age 61 years and older and those with disabilities free off-peak local bus travel across the country. The plan evolved from half-price local travel and free local travel through ad hoc local schemes. The taxpayer cost is more than £1 billion ($1.6 billion; £1 = $1.60 in 2013) a year. There have been calls for the scheme to be abolished or reduced in scope to save public expenditure. However, the scheme is very popular with those who hold concessionary travel passes and is popular generally. This paper describes the scheme and then considers the take-up rate, along with how it has increased over time. Effects on the travel behavior of older and disabled people in changes in trip patterns, trip purposes, and modal usage are then discussed. The study examined the evidence on the benefits that concessionary travel passes offer their holders; these benefits included quality of life, health, social inclusion, the process of ceasing to drive, and access to local services, all of which affect well-being. The wider benefits to society of concessionary travel passes and the value placed on them were considered. Although placing a monetary value on all the benefits is not possible, the benefits are large and must be considered in any discussion about abolishing or amending the scheme.
Comparing Fixed-Route and Demand-Responsive Feeder Transit Systems in Real-World Settings
Authors: Edwards Derek , Watkins Kari
Published: March 2014

This research presents a method for comparing fixed-route transportation systems and demand-responsive feeder transit systems by using passenger survey data, published transit schedules, and optimal routing techniques. Demand-responsive transportation can be used to improve transit service levels in low-demand areas. Because demand in cities can vary significantly across the region and by time of day, an effective means of determining when demand-responsive services can outperform fixed-route services, and vice versa, is needed. This research builds on existing comparison techniques that focus on gridded street systems and expands the techniques to include all types of street networks, transit schedules, and passenger demand levels. The generic techniques are presented and a case study is given for Atlanta, Georgia, to determine where demand-responsive feeder systems could be implemented to improve customer satisfaction and reduce operating costs.
Metropolitan Transit Agency's Experience Operating General-Public Demand-Responsive Transit
Authors: Becker Jeff , Teal Roger , Mossige Rebecca
Published: March 2014

Since 2000 the Regional Transportation District of Denver, Colorado, has operated general-public demand-responsive transportation, branded as Call-n-Ride (CnR), in 21 service areas in a variety of settings throughout the district. CnR was developed for use in communities where bus service is not cost-effective because of low to moderate residential and employment density, circuitous street networks, and dispersed geographic and temporal travel patterns but where demand is suf-ficient to warrant internal circulation or connection to the metropolitan transit network. The CnR service is characterized by a range of demand-responsive transportation service configurations, incorporating many-to-many services, scheduled checkpoints, zones, and flex routes tailored to the topography and travel patterns of each service area. In this paper, an analysis of data obtained primarily from CnR's automated scheduling system provides insight into the operations of demand-responsive transportation services for the general public. This insight may be used in other metropolitan areas for assessment of the feasibility of a CnR system.
Impact of Curbside Parking on Travel Time and Space Mean Speed of Nonmotorized Vehicles
Authors: Ye Xiaofei , Chen Jun
Published: March 2014

Curbside parking is an important component of a parking system. This type of parking can significantly affect traffic performance because of both the required roadway resources and the operational characteristics of parking maneuvers. To analyze the traffic performance of nonmotorized vehicles influenced by curbside parking, this study gives a quantitative analysis of the influence of curbside parking on travel time and space mean speed. The travel time and travel speed data of nonmotorized vehicles moving in road sections with curbside parking and barriers between motorized and nonmotorized vehicles were gathered by observers. A proportional hazard-based duration model is proposed to analyze the influential factors related to curbside parking, including the effective width of a bicycle lane; inbound and outbound parking maneuvers, double parking, and load–unload activities; and the time influence rate. Results show that curbside parking has a significant impact on the travel speed of nonmotorized vehicles. Results also indicate that the effective lane width shows a positive effect on travel speed, while inbound and outbound parking maneuvers and the time influence rate show a negative effect on travel speed. In addition, various factors can modify travel speed; the model can be used to estimate travel speed under assumed conditions. It is hoped that this study will help to improve the planning and management of curbside parking.
Toward People's Cities through Land use and Transport Integration
Authors: Hidalgo Dario , Pai Madhav , Carrigan Aileen , Bhatt Amit
Published: March 2014

Between 2005 and 2012, India's Jawaharlal Nehru National Urban Renewal Mission (JnNURM) invested US$20 billion in urban infrastructure and basic services for the urban poor. The transport program under JnNURM is an important advance, helping cities with policies and funding for moving people, not vehicles. Nevertheless, this program has not sufficiently shifted investment in the urban transport sector from road widening and road expansion to sustainable transport. Urban characteristics and transport needs of Indian cities derived from interviews with stakeholders and a literature review are presented. Key improvements for Indian urban transport policy are suggested: (a) reinforce the link between land use and transport to allow preservation of the built environment in existing cities and development of new accessible, dense, and mixed used developments in the fringes; (b) advance the preparation and implementation of comprehensive mobility plans, in close connection with master plans and JnNURM budget allocations; (c) introduce performance measurements of key transport indicators at the citywide level—people served, modal share, travel time, traffic fatalities, and transport tailpipe emissions; and (d) develop capacity-building programs for project planning and delivery at the city level and for evaluation and monitoring at the state and national levels. There is no claim that expansion is not needed, but it should not be the main priority of public investments in the transport sector. Recommendations for India may apply to other rapidly urbanizing and motorizing countries.
Assessment of Public–Private Partnership in Traveler Information Provision
Authors: Bagloee Saeed Asadi , Kermanshah Mohammad , Bozic Claire
Published: March 2014

Making efficient use of transportation infrastructure has always been a concern. Traveler information provisions (TIPs) assist commuters in making better travel decisions and therefore lead to increased mobility and more efficient travel. The ongoing economic crisis and shrinking public funding have made the public–private partnership (PPP) an at tractive instrument for promoting TIP. Such initiatives have been much discussed in developed countries. The use of PPP to fund public projects in developing countries, however, is in its infancy, and the related issues do not receive adequate attention in the literature. In this study, PPP opportunities in TIP were assessed in the case of a city in a developing country, Tehran, Iran. Factors contributing to TIP effectiveness were studied by analyzing commuters’ behavioral changes in response to current radio traffic information. Analysis was conducted with multinomial logit and nested logit models. From this analysis, commuter characteristics, trip purpose, and content of radio traffic information were identified as factors contributing to drivers’ willingness to divert. These findings directed the research to some potential markets and strategies for investment in TIPs. The literature was reviewed to identify some challenges and opportunities of PPP in past experience as well as special regional constraints. On the basis of the modeling results and literature review, business models for PPP in TIPs were outlined. Key findings are that (a) data integration and customization are essential; (b) with respect to purchasing behavior, the market has to be stratified into commuter and corporate markets; and (c) the market for Global Positioning System–based services is promising.
Low-Mass Urban Microcars for the Emerging Vehicle Markets of Megacities
Authors: Cahill Eric C. , Taylor Bill , Sperling Dan
Published: March 2014

For rapidly growing vehicle markets, small, low-mass vehicles show promise. New regulatory norms that take into account the differing operating environments and demands of these vehicles are needed. The potential for such vehicles to meet the demands of consumers and transportation systems in emerging markets—particularly in dense megacities, initially as commercial last-mile transportation and more broadly for private automobile consumers—is explored. A proposal for a regulatory template for these urban microcars considers potential energy, emissions, and safety impacts, borrowing features from the low-speed vehicle category in the United States and the L5e motor tricycle and L7e heavy quadricycle norms in the European Union.
Transition to a Transit City
Authors: Song Ziqi
Published: March 2014

Over the past three decades, the urban transportation system in Beijing has been undergoing tremendous changes. Beijing has been transformed from a city dominated by nonmotorized transportation to an almost car-saturated city. To combat the ever-growing traffic gridlock, the city in recent years has been working proactively on fulfilling its long-term vision: building a transit city. This study presents the city's development of a more sustainable transportation system from a mobility culture perspective. More specifically, the focus is on these three aspects: travel demand, mobility patterns, and transportation policy.
Modeling Pedestrian Delay and Level of Service at Signalized Intersection Crosswalks under Mixed Traffic Conditions
Authors: Nagraj R. , Vedagiri P.
Published: March 2014

The objectives of this study were to identify the factors affecting pedestrian level of service (LOS) at signalized intersection crosswalks under mixed traffic conditions and to propose a suitable method for estimating pedestrian LOS. The study attempted to develop a pedestrian LOS model for signalized intersection crosswalks in Mumbai, India, by using pedestrians’ perceptions of various influencing factors. The important factors considered to develop the model were turning traffic, through traffic, number of pedestrians, and pedestrian delay. Pedestrian delay is one of the key performance indicators for signalized intersection crosswalks; it is necessary to estimate delays accurately to assess LOS. As in the Highway Capacity Manual method, pedestrian delay can be calculated with the help of Webster's delay model, which assumes pedestrians arrive at a uniform rate at an intersection and all will comply with the signal; however, that assumption is not true for the Indian scenario. A pedestrian delay model for Indian conditions was developed by considering nonuniform arrival rate and signal noncompliance behavior. A video graphic technique was conducted for six selected crosswalks. A questionnaire survey was conducted to obtain the perceived LOS of pedestrians. Pedestrian delay was found with the use of the new model. A Pearson correlation analysis was done to find the significant factors that affect LOS. With perceived LOS as a dependent variable and significant factors as independent variables, stepwise regression was done to develop the model that fit for urban mixed traffic conditions.
Has Transportation Demand of Shanghai, China, Passed Its Peak Growth?
Authors: Zhao Zhan , Zhao Jinhua , Shen Qing
Published: March 2014

On the basis of four comprehensive transportation surveys in Shanghai, China, this study examined the latest trends in Shanghai's travel demand; investigated their social, economic, and spatial drivers; and compared the pace of travel demand growth in three periods: 1980s to early 1990s, early 1990s to mid-2000s, and mid-2000s to the present. The demand growth was relatively slow in the first period and then sped up in the second before it returned to a slower pace in the third period. As for trip purpose, Shanghai's travel is much more diversified than previously, with an increasing share of noncommuting trips (from 28% in 1995 to 46% in 2009). Spatially, travel demand is dispersed from the central district to peripheral districts because of urban expansion and decentralization and from Puxi (west of the Huangpu River) to Pudong (east of the Huangpu River) as a result of significant economic development of the Pudong New Area. Both spatial diffusion and purpose diversification favor the convenience and flexibility of private motor vehicles. Driven by rapid motorization, vehicle travel is growing at a much faster pace than person travel. Overall, the annual growth rate for travel demand in Shanghai reached its peak in 2004 for both person trips and vehicle trips. In absolute numbers, person trip growth has peaked, but vehicle trip growth has not. In response to the growing demand, especially rapid motorization, the local government has made tremendous investments in road infrastructure and public transit, and it has attempted to manage demand through vehicle ownership control.
Direct Ridership Models of Bus Rapid Transit and Metro Systems in Mexico City, Mexico
Authors: Duduta Nicolae
Published: March 2014

Direct ridership models (DRM) have been introduced in the United States as an alternative to four-step travel demand modeling. DRMs can be used to obtain quick, order-of-magnitude estimates of transit patronage at a fraction of the cost of a full travel demand model and are more adept at capturing the effects of smart growth on transit rider-ship. The relatively low cost, flexible data requirements, and rapidity make these models particularly suited to developing world cities. Yet these cities still rely almost exclusively on full travel demand models to advise investments in new transit infrastructure. In doing so, cities often use old data and out-of-date household surveys and do not capture important recent changes in travel patterns. Mexico City, Mexico, is taken as a case study to illustrate the benefits of using DRM models in a developing world context. Ridership models are developed for the city's bus rapid transit and Metro networks to study how land use and service and station attributes affect ridership for each mode and also how connections between bus rapid transit and Metro affect each other's ridership. The two systems are complementary, each getting ridership benefits from connecting to the other. Implications of findings for transport policy in Mexico City are discussed, as well as some shortcomings of DRM models, particularly their difficulty in accounting for informal transit.
Evaluating Private Bus Operators’ Willingness to Participate in Transit Improvements in Mexico
Authors: Dodero Abel Lopez , Casello Jeffrey M. , Molinero Angel R. Molinero , Cotera Daniel Vazquez
Published: March 2014

Inputs are provided for the decision-making process of transit improvements in developing countries. With an analysis of the willingness of private bus operators to participate in transit improvements, political feasibility can be assessed, and the likelihood of successful implementation can be increased. Data from 156 surveys conducted in cities in Mexico are used to develop probabilistic models that quantify the influence of private bus operators’ characteristics, perceptions about business and operating efficiencies, and their relationship with government on their willingness to participate. Evidence shows that several elements can increase the willingness of private operators to participate in government-led proposals. These elements include the level of trust and communication between private bus operators and government authorities, the economic power of private bus operators, and the attachment to the status quo. Several features are shown to limit operators’ willingness to participate, including the model of operation, likelihood of lost revenue through taxation, and concerns about the potential modifications of their legal rights to operate. An analysis of Mexico City, Mexico, and surrounding areas demonstrates the need to establish a well-defined strategy for engaging private bus operators in transit improvements; failure to do so has resulted in much less trust of government and led to more conflicts about future projects. The importance of analyzing private bus operators’ participative profiles in the assessment of transit improvements is revealed. Selected areas for improvements might present challenges for engaging private bus operators in proposed improvements.
Safety Evaluation of Discontinuing Late Nighttime Flash Operations at Signalized Intersections
Authors: Lan Bo , Srinivasan Raghavan
Published: March 2014

This study examined the safety impacts of converting late nighttime flash operation to normal phasing operation at signalized intersections by using the empirical Bayes, the univariate full Bayes, and multivariate full Bayes before-and-after methods. Data were obtained from the North Carolina Department of Transportation for 61 treatment sites and 395 reference intersections that remained on late nighttime flash operation from 2000 to 2007. The results from the empirical Bayes method are almost identical to those of the univariate full Bayes. The full Bayes method offered more flexibility in selecting the functional form of expected crashes at similar sites (similar to the safety performance function in the empirical Bayes) and in addressing uncertainty in the data. Compared with the univariate full Bayes, the multivariate full Bayes with the multivariate Poisson lognormal (MVPLN) model provided better results based on much lower deviance information criterion values. The MVPLN model was favored and the recommended crash reduction factors are 48% (±6%), 53% (±8%), and 57% (±7%) for nighttime total, injury and fatal, and frontal impact crashes, respectively.
Safety Evaluation of Converting Traffic Signals from Incandescent to LED Bulbs
Authors: Srinivasan Raghavan , Carter Daniel , Smith Sarah , Lan Bo
Published: March 2014

Data from 282 signalized intersections in Charlotte, North Carolina, were used to examine the safety effect of converting the signals to composite LED bulbs. An empirical Bayes before-and-after method was used for the evaluation. Since this was a blanket installation by the city of Charlotte, a comparison group of stop-controlled intersections was used to account for possible trends during the study period. Crash modification factors (CMFs) were estimated for three- and four-leg intersections for eight different crash types including crashes at dawn and dusk and in dark conditions. For three-leg intersections, all CMFs were higher than 1.0; this factor indicates a possible increase in crashes due to the LEDs. However, none of these CMFs were statistically different from 1.0 at the .05 significance level. For four-leg intersections, the CMFs associated with rear-end crashes were lower than 1.0 and statistically significant at the .05 level; this finding indicates a reduction in these crash types following the changeover to the LEDs. There was substantial difference between the sites in terms of the effect of the LEDs. The reasons for these differences are not known at this time. Future research should investigate whether LEDs are more or less beneficial depending on the characteristics of the intersection including type of area, sight distance, traffic volume, and phasing scheme.
Severity Distribution Functions for Freeway Segments
Authors: Geedipally Srinivas Reddy , Bonneson James A. , Pratt Michael P. , Lord Dominique
Published: March 2014

To date, the focus of modeling efforts for freeway safety has been on developing safety prediction functions and crash modification factors, with only limited consideration for crash severity distributions. As a result, relatively little is known about the safety effects of design elements such as lane width, rumble strips, and longitudinal barriers on crash severity. In some cases, countermeasures are implemented with the intent to reduce fatal crashes, but the effect of these treatments on less severe crashes is not well understood. Research was conducted to develop severity distribution functions (SDFs) to predict the proportion of crashes in each severity category as a function of roadway geometric design elements and traffic control features. The SDFs were calibrated with freeway segment data from California, Maine, and Washington State. The findings from this research show that barrier presence, increased traffic volume, increased lane width, and urban area type reduce the proportion of high-severity crashes. At the same time, the presence of rumble strips and horizontal curvature increases the proportion of high-severity crashes. These SDFs can be applied along with safety prediction functions and crash modification factors to obtain more precise estimates of the safety effects of design decisions.
Development of Relationships between Safety and Congestion for Urban Freeways
Authors: Harwood Douglas W. , Bauer Karin M. , Potts Ingrid B.
Published: March 2014

The development of relationships between safety and congestion is documented; traffic volume, speed, and crash data by 15-min periods for urban freeways in the areas of Seattle, Washington, and Minneapolis–Saint Paul, Minnesota, were used. The safety–congestion relationships were developed to provide a basis for estimating the safety effects of design treatments intended to reduce nonrecurrent congestion and increase travel time reliability. The relationships were developed with traffic volume and speed data from detectors in individual lanes for 564 urban freeway segments during study periods of up to 3 years. Traffic crash records were obtained for the same time periods as the volume and speed data. The U-shaped relationship between crash rate per million vehicle miles of travel and traffic density (the level-of-service measure for freeways) was found, with the highest crash rates at low and high traffic densities and the lowest crash rates in the middle range of traffic densities. The high crash rates at lower traffic densities represent predominantly single-vehicle crashes, whereas the high crash rates at higher traffic densities represent predominantly multiple-vehicle crashes. Quantitative safety–congestion relationships were developed for the range of traffic densities from 20 to 78 passenger cars per hour per lane, corresponding to the level-of-service range from C to F.
Safety Effects of Horizontal Curve and Grade Combinations on Rural Two-Lane Highways
Authors: Bauer Karin M. , Harwood Douglas W.
Published: March 2014

The safety effects of horizontal curves and grades on highways have been quantified separately, but it is not currently known whether or how the safety performance of horizontal curves interacts with that of grades. Although the first edition of the AASHTO Highway Safety Manual provides crash modification factors for the safety effects of horizontal curvature and percent grade on rural two-lane highways, the manual does not have a method for accounting for the interactions between these effects. In other words, in the Highway Safety Manual procedures for rural two-lane highways, the safety effect of a horizontal curve is the same whether the curve is located on a level roadway, a straight grade, or a vertical curve. Similarly, the safety effect of a straight grade is the same whether it is located on a tangent roadway or horizontal curve. Researchers have always supposed that there are interactions between the safety effects of horizontal and vertical alignments, but these interactions have not been demonstrated in a form useful for safety prediction. The results of research undertaken to quantify the safety effects of five types of horizontal and vertical alignment combinations based on Highway Safety Information System data and crash records from 2003 to 2008 in Washington State are summarized. The outcome is a set of safety pre diction models for fatal and injury and property-damage-only crashes. To present the results in a form suitable for incorporation into the Highway Safety Manual, crash modification factors representing safety performance relative to level tangents were developed from these models for each of the five combinations.