Incorporating refuelling behaviour and drivers’ preferences in the design of alternative fuels infrastructure in a city

The purpose of this article is to present an optimization model to plan the deployment strategy for hydrogen refuelling stations in a city when Origin–Destination (OD) data are not available. This model considers two objectives: to maximize the traffic covered by the selected hydrogen refuelling stations and minimize the average distance of the city’s inhabitants to the nearest hydrogen refuelling station. As OD data are assumed to be unavailable, the clustering of stations in the highest traffic zones is prevented by a new constraint that takes into account information on the distribution of existing conventional refuelling stations. This model is applied to Seville, a city in Southern Spain of about 140 km² with a population of around 700,000. This application uses the results of a survey of more than 200 Sevillian drivers on their current refuelling tendencies, their willingness to use alternative fuel vehicles and their minimum requirements (regarding maximum distance to be travelled to refuel and number of stations in the city) when establishing a network of alternative refuelling stations.     

Has the transport-led economic growth effect reached a peak in China? A panel threshold regression approach

Using China’s province-level panel data from 1987 to 2010, this study explores the optimal level of transport infrastructure accumulation maximizing the growth rate. We investigate under what circumstances can additional transportation infrastructure capacity positively affect economic growth, based on panel threshold regression models. Our empirical findings suggest that there is a non-monotonic relationship between the stock of transport infrastructure and the long-run growth rate. The magnitude of transport-led economic growth effect significantly depends on the level of the existing transport network. The empirical results identify two endogenous cut-off points of efficiency of transport-led economic growth effect. When the highway network density is lower than 0.17 km/km², an insignificant positive relationship between highway infrastructure accumulation and economic growth was found. When the highway density is estimated between 0.17 and 0.38 km/km² or higher than 0.38 km/km², expanding the highway network has a significant positive effect on economic growth, but the magnitude of the impact is weaker in the latter, with the estimated coefficients equal to 0.23 and 0.09 respectively. Although China still enjoys a positive economic growth effect led by building more large-scale highway infrastructure, the magnitude of the effects of most provinces in China has already passed the saturation point and continuously expanding the highway network is not very productive.     

Spatial and temporal distribution of expressway and its relationships to land cover and population: A case study of Beijing,China

The interaction between urban transport, land cover change and the distribution of population is a typical manifestation of the urbanization process. As high-grade road, expressway plays a significant role in promoting resource circulation and economic development. Based on the road distribution, land cover and population census data, this study specifically probed the relationship between the expressways and the land cover and population of Beijing. The results show that: (1) as the distance from an expressway increases, the amount of built-up land gradually decreased, and the transfer of land cover near the expressway was more intensive and frequent when compared with that of the whole city; (2) In 2010, a district that was less than 3 km from both sides of the expressway and which occupies one-quarter of the entire city had concentrations of 42% industrial land, 58% of settlement land, and 76% transportation land of the entire city; (3) As for Beijing, the population density was positively correlated to road density, and population density declined with a corresponding increase in buffer distance; (4) The ring area between the Fifth and the Sixth Ring Road featured the greatest density of expressways and the most dramatic changes in both land cover and population. According to our study, there’s a positive interactive feedback relationship between the expressways, land cover and population of Beijing. Also, due to the concentration of population, industry and transport system around the expressways, special attention should be paid to environmental pollution and the inhabitants’ health in this area.     

Extent and correlates of walking in the USA

This paper examines data about walking trips in the US Department of Transportation’s 2001 National Household Travel Survey. The paper describes and critiques the methods used in the survey to collect data on walking. Using these data, we summarize the extent of walking, the duration and distance of walk trips, and variations in walking behavior according to geographic and socio-demographic factors. The results show that most Americans do not walk at all, but those who do average close to thirty minutes of walking a day. Walk trips averaged about a half-mile, but the median trip distance was a quarter of a mile. A significant percentage of the time Americans’ walk was spent traveling to and from transit trips. Binary logit models are used for examining utility and recreational walk trips and show a positive relationship between walking and population density for both. For recreational trips, this effect shows up at the extreme low and high ends of density. For utility trips, the odds of reporting a walk trip increase with each density category, but the effect is most pronounced at the highest density categories. At the highest densities, a large portion of the effect of density occurs via the intermediary of car ownership. Educational attainment has a strong effect on propensity to take walk trips, for both for utility and recreation. Higher income was associated with fewer utility walk trips but more recreational trips. Asians, Latinos, and blacks were less likely to take utility walk trips than whites, after controlling for income, education, density, and car ownership. The ethnic differences in walking are even larger for recreational trips.     

Factors affecting public transportation,car, and motorcycle usage

This study established a hypothesis model based on the seemingly unrelated regression equations (SURE) model to investigate the relationship between public transportation, car, and motorcycle use in various townships in Taiwan and to analyse important factors that affect the usage of these modes. The SURE model was adopted because of the lack of a significant correlation between the dependent variables. The pairwise covariance analysis for any two of the three transportation modes revealed that the transportation modes could substitute for one another. Factors related to modal and demographic characteristics had different impacts on the usage of the three modes. The calculation of elasticity using different population densities and public transportation usage showed that when the ‘number of city bus routes’ was increased by 50% in areas with high population density and high public transportation usage, car usage decreased by 1.4%, which corresponds to 300,000 vehicles, and total CO₂ emissions reduced by 0.0204%. When the ‘total length of city bus routes’ was increased by 50%, the number of motorcycles used decreased by 83 million, and total CO₂ emissions reduced by 1.119%, which corresponds to 1.4 million tonnes of CO₂ emission. These findings suggest that these different factors had varying impacts on car and motorcycle usage in different areas. We therefore recommended that future transportation policies consider the varying transportation usage trends in different areas.     

Quantifying the environmental impacts of increasing high occupancy vehicle lanes in the United States

To what extent will increasing High Occupancy Vehicle (HOV) lane-kilometer incentivize carpooling and reduce emissions of air pollutants and greenhouse gases? To answer these questions, we develop a multiple regression model relating HOV lanes and other socioeconomic factors to carpooling propensity in all 50 U.S. states and the District of Columbia, then calculate the extent to which increasing HOV lane-kilometers would lead to reductions in carbon dioxide equivalent (CO₂e) and major air pollutants across the U.S., by state. Increasing HOV lane extent has the greatest potential to reduce annual CO₂e in the District of Columbia, followed by Hawaii and New York. The smallest potential is found in states with the lowest population density, led by North Dakota. We then explore the extent to which recommendations made at one level of data aggregation (that of individual states) may be valid for another level, such as individual counties. The only state with sufficient data available to disaggregate the model to the county level is California, where we found a lower potential for state-wide CO₂e emission reductions under the county-level model as compared to the state-level model (0.69% as compared to 1.08%, under the same hypothetical scenario), albeit with significant differences in emission reduction potential between counties with higher vs. lower population densities. This analysis demonstrates the potential to generate generalizable insight into the magnitude of vehicle emission reductions that might be achieved through expanding HOV lanes, and highlights the importance of data disaggregation in identifying the optimal locations for potential reductions.     

Walking,cycling and the urban form: A Heckman selection model of active travel mode and distance by young adolescents

Physical inactivity of children and adolescents is a major public health challenge of the modern era but, when adequately promoted and nurtured, active travel offers immediate health benefits and forms future sustainable and healthy travel habits. This study explores jointly the choice and the extent of active travel of young adolescents while considering walking and cycling as distinct travel forms, controlling for objective urban form measures, and taking both a “street-buffer” looking at the immediate home surroundings and a “transport-zone” looking at wider neighborhoods. A Heckman selection model represents the distance covered while cycling (walking) given the mode choice being bicycle (walk) for a representative sample of 10–15 year-olds from the Capital Region of Denmark extracted from the Danish national travel survey. Results illustrate the necessity of different urban environments for walking and cycling, as the former relates to “street-buffer” urban form measures and the latter also to “transport-zone ” ones. Results also show that lessening the amount and the density of car traffic, diminishing the movement of heavy vehicles in local streets, reducing the conflict points with the density of intersections, and intervening on crash frequency and severity, would increase the probability and the amount of active travel by young adolescents. Last, results indicate that zones in rural areas and at a higher percentage of immigrants are likely to have lower probability and amount of active travel by young adolescents.     

Walking to the bus: perceived versus actual walking distance to bus stops for older adults

The walking trip from an origin or destination to a bus stop or transit station can be a barrier to riding transit for older adults (over age 60) who may walk more slowly than others or experience declining physical mobility. This article examines the relationship between transit ridership and proximity to fixed-route transit stations using survey data for older adults in Buffalo and Erie County, New York. Demographic and socio-economic characteristics—including age, sex, race, income, possessing a driver’s license, frequency of leaving home, and personal mobility limitations—are tested but do not display, in bi-variate analysis, statistically significant differences for transit riders versus non-transit riders. However, features of the built environment—including distance (actual and perceived) between home and transit stop, transit service level, population density, number of street intersections, metropolitan location, and neighborhood crime (property and violent) rate—display statistically significant differences for transit riders versus non-transit riders. Both objective and perceived walking distances to access fixed-route transit show statistically significant differences between transit riders and non-transit riders. Average walking distance from home to transit for non-transit riders—who mostly live in suburbs—is three times greater than average walking distance between home and the nearest transit stop for transit riders—who mostly live in the central city. When asked how near a bus stop is to their homes, transit riders slightly overestimate the actual distance, while non-transit riders underestimate the distance.     

Cooperation in transit delivery in West German metropolitan areas

West Germany is densely populated, averaging 245 inhabitants/km², but varying widely between urban agglomerations and rural areas. Transport volume has increased by 40% since 1970, with virtually all growth due to private automobiles. Since 1981 public transit has been suffering from decreasing demand.A 1964 Expert's Report to the German federal government was the stimulus for initiating an effective funding mechanism for new public transit construction. In 1965 Germany's first federated transit authority was founded for the region of Hamburg.Principal among the goals of any cooperative agreement among transit companies are improvements for the passengers and improvement of revenues for the companies. To attain these ends, two distinct forms of transit aggrements have been developed in Germany: transit cooperative (Verkehrsgemeinschaft) and transit federation (Verkehrsverbund). The former is more suitable for smaller to medium-sized towns, while the latter is more suitable for larger cities. The two types are described in this article.German transit federations during the 1970s succeeded in significantly increasing ridership, while during the 1980s patronage has either remained steady or has declined. Yet transit federations showed much better perfomance than did public transit in general. In terms of costs and revenues, no public transit organization in Germany is able to break even; deficits vary between 42% and 55%. The author concludes, however, that hidden subsidies for automobile traffic are far higher, because of environmental damage and the high social cost of traffic accidents.     

Isocyanic acid and ammonia in vehicle emissions

Vehicles are considered to be an important source of ammonia (NH₃) and isocyanic acid (HNCO). HNCO and NH₃ have been shown to be toxic compounds. Moreover, NH₃ is also a precursor in the formation of atmospheric secondary aerosols. For that reason, real-time vehicular emissions from a series of Euro 5 and Euro 6 light-duty vehicles, including spark ignition (gasoline and flex-fuel), compression ignition (diesel) and a plug-in electric hybrid, were investigated at 23 and −7 °C over the new World harmonized Light-duty vehicle Test Cycle (WLTC) in the Vehicle Emission Laboratory at the European Commission Joint Research Centre Ispra, Italy. The median HNCO emissions obtained for the studied fleet over the WLTC were 1.4 mg km⁻¹ at 23 °C and 6 mg km⁻¹ at −7 °C. The fleet median NH₃ emission factors were 10 mg km⁻¹ and 21 mg km⁻¹ at 23 and −7 °C, respectively. The obtained results show that even though three-way catalyst (TWC), selective catalytic reduction (SCR), and NOx storage catalyst (NSC) are effective systems to reduce NOx vehicular emissions, they also lead to considerable emissions of the byproducts NH₃ and/or HNCO. It is also shown that diesel light-duty vehicles equipped with SCR can present NH₃ emission factors as high as gasoline light-duty vehicles at both, 23 and −7 °C over the WLTC. Therefore, with the introduction in the market of this DeNOx technology, vehicular NH₃ emissions will increase further.     

The impact of Low Emission Zones on particulate matter concentration and public health

A common policy for reducing particulate matter concentrations in the European Union is the introduction of Low Emission Zones (LEZs), which may only be entered by vehicles meeting predefined emission standards. This paper examines the effectiveness of LEZs for reducing PM₁₀ levels in urban areas in Germany and quantifies the associated health impacts from reduced air pollution within the zones. We employ a fixed effects panel data model for daily observations of PM₁₀ concentrations from 2000 to 2009 and control, inter alia, for local meteorological conditions and traffic volume. We apply the regression outputs to a concentration response function derived from the epidemiological literature to calculate associated health impacts of the introduction of LEZs in 25 German cities with 3.96 million inhabitants. Associated uncertainties are accounted for in Monte-Carlo simulations. It is found that the introduction of LEZs has significantly reduced inner city PM₁₀ levels. We estimate the total mean health impact from reduced air pollution in 2010 due to the introduction of stage 1 zones to be ∼760 million EUR in the 25 LEZ cities in the sample, whereas total mean health benefits are ∼2.4 billion EUR for the more stringent stage 2 zones when applied in the same cities.     

Residential built environment and walking activity: Empirical evidence of Jane Jacobs’ urban vitality

This study intends to empirically verify Jacobs’ urban vitality theory, which was based on the observations of her New York City neighborhood in the mid-20th century. To examine the relationship between the residential built environment and walking activity, we used telephone survey data consisting of 1823 valid samples from across Seoul, a city characterized by a high population density and a well-established public transportation system. Respondents were asked questions about their residential location, their demographic and socioeconomic characteristics, and their walking activities. This study then used geographic information systems to measure objective indicators of built environment variables within 500-meter buffer areas based on the home addresses of the respondents. Then, this study constructed multilevel regression models with walking activity as the dependent variable. Our results indicated that walking activity is associated with Jacobs’ six conditions for urban vitality, including land use mix, density, block size, building age, accessibility, and border vacuums.     

Persistence of walking in Chile: lessons for urban sustainability

ABSTRACT

An extensive body of work from the urban planning, health, and other disciplines has documented the importance of walking to urban sustainability from health, safety, security, environmental and other perspectives. These studies come mainly from countries in North America and Europe, where the majority of the population relies on cars for transportation. Notwithstanding, in many countries in the Global South, walking remains a majority transport mode, while cars increasingly dominate the urban streetscape, but are accessible only to a minority of the population. Chile provides fertile terrain for studying this phenomenon. This article reviews current practice and recent research of walking in Chile, in light of international findings regarding walkability, equity and urban sustainability. To elaborate an overview of the depth and breadth of walking in Chile, an interdisciplinary team conducted a literature review, examined relevant case study material from experience from Chile and in particular from Santiago, and triangulated this mainly qualitative data with results from the origin-destination survey applied in Chile’s main cities, Chilean traffic safety data) and results from official transport reports of other Latin American cities [Tirachini, A. (2019). South America: The challenge of transition. In J. Stanley & D. Hensher (Eds.), A research agenda for transport policy. Northampton, MA: Edward Elgar Publishing]. Findings show that despite priority public investments that have largely prioritised infrastructure for cars, walking in Chile has remained as the majority transport mode up until today, especially for lower-middle income groups, and particularly for care-related tasks performed mainly by women. In this sense, walking in Chile has proven remarkably persistent. The importance of walking as the main transport mode, against the odds, reflects economic, cultural, and urban form determinants, which are explored in this article. Furthermore, a recent upsurge in public interest and community design initiatives to improve walking, particularly the generation of a Chilean approach to “complete streets” has emerged, opening up opportunities to challenge Chile’s version of automobility in favour of more equitable, active and public transportation modes. There is, therefore, in Chile an opportunity to prioritise the walking mode, improve infrastructure for walkers and build from preserving current high pedestrian modal shares, rather than having to reverse widespread car use, as occurs in many countries in Europe and North America. This potential is highly relevant as these conditions are similar to those in other Latin American cities and, potentially, other cities elsewhere in the Global South.     

Metropolitan sprawl measurement and its impacts on commuting trips and road emissions

This study measures urban form as indicators of metropolitan sprawl and explores its impact on commuting trips and NO_x and CO₂ emissions from road traffic in all metropolitan statistical areas (MSAs) and four groups’ MSAs separated by population in the continental United States. Encompassing all MSAs, the study adds the accessibility factor to four existing factors: density, land use mix, centeredness, and street connectivity. The study establishes multivariate regression models between urban form, commuting trips, and emissions from road traffic while controlling for socioeconomic conditions. The study shows that urban form index and five urban form factors have a statistically significant association with commuting trips, NO_x and CO₂ emissions from road traffic. In four MSA groups as determined by MSA population size, higher values of urban form factors (i.e., lower sprawl) are statistically associated with more walking commuters. On the other hand, higher values of urban form factors are associated with fewer commuting vehicles per household in large MSAs with the moderate effect, a lower average commuting drive time in medium and small MSAs, and more commuters using public transportation in medium and large MSAs. This study provides an urban form index covering all metropolitan areas in the continental United States by adding another urban form factor, and the findings show that urban form factors have different effects on mode choices, drive time, and emission from road traffic depending on the MSA population size.     

Lead emission rates from gasoline engines—a legislative and in‐use emission rate study of U.K. and U.S. to 1990

Concern for reduction in air‐borne lead emission from passenger cars is focussed on both the legislative and practical steps in reducing lead in gasoline. The historical trends and projections to 1990 of present U.S. and U.K. policies are examined in terms of a baseline passenger car lead emission rate, g.km^‐1. It is likely that should the U.K. adopt a lead‐free petrol the decrease in lead emissions will only partially parallel the present U.S. experience from a start‐up date typically post 1990. The U.S. gasoline pool philosophy has permitted lead levels in gasoline to remain high; a pitfall which the U.K./EEC should avoid.     

New evidence on walking distances to transit stops: identifying redundancies and gaps using variable service areas

The percentage of the population being served by a transit system in a metropolitan region is a key system performance measure but depends heavily on the definition of service area. Observing existing service areas can help identify transit system gaps and redundancies. In the public transit industry, buffers at 400 m (0.25 miles) around bus stops and 800 m (0.5 miles) around rail stations are commonly used to identify the area from which most transit users will access the system by foot. This study uses detailed OD survey information to generate service areas that define walking catchment areas around transit services in Montreal, Canada. The 85th percentile walking distance to bus transit service is found to be around 524 m for home-based trip origins, 1,259 m for home-based commuter rail trip origins. Yet these values are found to vary based on our analysis using two statistical models. Walking distances vary based on route and trip qualities (such as type of transit service, transfers and wait time), as well as personal, household, and neighbourhood characteristics. Accordingly, service areas around transit stations should vary based on the service offered and attributes of the people and places served. The generated service areas derived from the generalized statistical model are then used to identify gaps and redundancies at the system and route level using Montreal region as an example. This study can be of benefit to transport engineers and planners trying to maximize transit service coverage in a region while avoiding oversupply of service.     

Using topology and neighbor information to overcome adverse vehicle density conditions

Vehicular networks supporting cooperative driving on the road have attracted much attention due to the plethora of new possibilities they offer to modern Intelligent Transportation Systems. However, research works regarding vehicular networks usually obviate assessing their proposals in scenarios including adverse vehicle densities, i.e., density values that significantly differ from the average values, despite such densities can be quite common in real urban environments (e.g. traffic jams). In this paper, we study the effect of these hostile conditions on the performance of different schemes providing warning message dissemination. The goal of these schemes is to maximize message delivery effectiveness, something difficult to achieve in adverse density scenarios. In addition, we propose the Neighbor Store and Forward (NSF) scheme, designed to be used under low density conditions, and the Nearest Junction Located (NJL) scheme, specially developed for high density conditions. Simulation results demonstrate that our proposals are able to outperform existing warning message dissemination schemes in urban environments under adverse vehicle density conditions. In particular, NSF reduces the warning notification time in low vehicle density scenarios, while increasing up to 23.3% the percentage of informed vehicles. As for high vehicle density conditions, NJL is able to inform the same percentage of vehicles than other existing approaches, while reducing the number of messages up to 46.73%.     

Walk score® and its potential contribution to the study of active transport and walkability: A critical and systematic review

The Walk Score® index has become increasingly applied in studies of walking and walkability. The index assesses the “walking potential” of a place through a combination of three elements: the shortest distance to a group of preselected destinations, the block length, and the intersection density around the origin. The Index links a gravity-based measure (distance accessibility), with topological accessibility (street connectivity) measured by two complementary indicators that act as penalties in the final score (linearly expanded in the range 0–100). A systematic review of Scopus® and Web of Science® was conducted with 42 journal articles eventually being evaluated. Research was primarily undertaken in North American urban geographies. Analysis of walkability using Walk Score® is inconsistent. Twenty-nine papers do not exclusively relying on Walk Score® as a single measurement of walkability and add further estimates to better capture the multiple dimensions of walkability. In 33 studies the Walk Score® was used as an independent variable, and only once as a mediating-moderating variable. In eight papers (18%) the Walk Score® was a part of a bivariate correlation model. On no occasion was it used as a dependent variable. Results tend to only partly support the validity of Walk Score®. The paper concludes that the Index is best understood as a surrogate measure of the density of the built environment of a specific neighborhood that indicates utilitarian walking potential. Implications for, and potential areas of, future research are discussed.     

Nature and/or nurture? Analyzing the determinants of transit ridership across US urbanized areas

Public subsidy of transit services has increased dramatically in recent years, with little effect on overall ridership. Quite obviously, a clear understanding of the factors influencing transit ridership is central to decisions on investments in and the pricing and deployment of transit services. Yet the literature about the causes of transit use is quite spotty; most previous aggregate analyses of transit ridership have examined just one or a few systems, have not included many of the external, control variables thought to influence transit use, and have not addressed the simultaneous relationship between transit service supply and consumption. This study addresses each of these shortcomings by (1) conducting a cross-sectional analysis of transit use in 265 US urbanized areas, (2) testing dozens of variables measuring regional geography, metropolitan economy, population characteristics, auto/highway system characteristics, and transit system characteristics, and (3) constructing two-stage simultaneous equation regression models to account for simultaneity between transit service supply and consumption. We find that most of the variation in transit ridership among urbanized areas – in both absolute and relative terms – can be explained by factors outside of the control of public transit systems: (1) regional geography (specifically, area of urbanization, population, population density, and regional location in the US), (2) metropolitan economy (specifically, personal/household income), (3) population characteristics (specifically, the percent college students, recent immigrants, and Democratic voters in the population), and (4) auto/highway system characteristics (specifically, the percent carless households and non-transit/non-SOV trips, including commuting via carpools, walking, biking, etc.). While these external factors clearly go a long way toward determining the overall level of transit use in an urbanized area, we find that transit policies do make a significant difference. The observed range in both fares and service frequency in our sample could account for at least a doubling (or halving) of transit use in a given urbanized area. Controlling for the fact that public transit use is strongly correlated with urbanized area size, about 26% of the observed variance in per capita transit patronage across US urbanized areas is explained in the models presented here by service frequency and fare levels. The observed influence of these two factors is consistent with both the literature and intuition: frequent service draws passengers, and high fares drive them away.     

Optimal deployment of emergency rescue stations in an urban transportation corridor

This paper addresses the deployment issue of emergency rescue stations in an urban transportation corridor, with an aim to effectively reduce the casualties in traffic accidents. On the basis of urban population density, an accident rate distribution function for a corridor is first presented and calibrated, and a damage cost function is proposed to capture the correlation between rescue time and deteriorating health condition of injured passengers. A continuum model is then developed for determining the optimal number and locations of the rescue stations along the corridor and the medical service resource distribution at rescue stations subject to a capital budget constraint. The solution properties of the proposed model are explored analytically. Numerical examples are provided to show the effects of population density, urban form and different deployment schemes (even and uneven) on the rescue station locations. A case study of Wuhan China is employed to illustrate the effectiveness of the proposed methodology in improving the performance of the emergency rescue system.