Social influence in the global diffusion of alternative fuel vehicles – A meta-analysis

Alternative fuel vehicle technologies are needed to mitigate rising greenhouse gas emissions from transport. Social influence is integral to the diffusion of private vehicles which are highly visible and fulfil practical as well as social functions. This paper provides the first meta-analysis of empirical studies which measure the strength of social influence on consumer vehicle choice. A systematic literature review identified 21 studies that examined three types of social influence: interpersonal communication; neighbourhood effect; and conformity with social norms. A random effects meta-analysis found a significant and small to moderate effect of social influence on vehicle choices (r = 0.241, p < 0.001). The overall effect size did not vary significantly between types of social influence nor between types of vehicle (conventional or alternative fuel). However, further analysis using meta-regression found that heterogeneity in social influence effect size across studies was explained by differences in countries' cultural receptiveness to normative influence. These findings have important implications for policy and modelling analysis of alternative fuel vehicle adoption, for which diffusion is both a socially and culturally-mediated process.     

New method to estimate local and system-wide effects of level rail crossings on network traffic flow

This paper makes local and aggregate estimates of the effects of 152 level crossings in the Melbourne metropolitan area, Australia on traffic congestion in the morning peak period (7 am–9 am). A new method, including micro-simulation of a range of rail crossing configurations, is used to inform a network model which makes aggregate estimates of impacts on all traffic.Relationships between train frequency and percentage change in vehicle travel time and volume were identified. These equations can predict change in travel time/traffic flow caused by rail level crossings based on rail crossing closures and train frequency.Overall, Melbourne's level crossings result in an average increase in travel time of 16.1% for vehicle traffic on links with a level crossing. However on average a level crossing reduces the volume of vehicles on these links by 5.9% as a result of traffic diversion. These values are higher in middle suburbs where train arrivals and crossing closure times at level crossings are more frequent.The aggregate effect of all 152 level rail crossings on all traffic in Melbourne is a travel time change from 1.81 to 1.82 min/km (an increase of around 0.3%). The number of congested links in Melbourne increases by 0.9% while the total delay increases by 0.7%. These network wide effects are not large compared to localised effects because road links affected directly by crossings represent a very small part of the overall network. Additionally, network effects also include traffic diversion impacts which will counteract some of the immediate impacts on a localised scale. However, it is significant that the very small element of the system can have even a measurable effect on aggregate traffic congestion.     

A supply chain network design model for biomass co-firing in coal-fired power plants

We propose a framework for designing the supply chain network for biomass co-firing in coal-fired power plants. This framework is inspired by existing practices with products with similar physical characteristics to biomass. We present a hub-and-spoke supply chain network design model for long-haul delivery of biomass. This model is a mixed integer linear program solved using benders decomposition algorithm. Numerical analysis indicates that 100 million tons of biomass are located within 75 miles from a coal plant and could be delivered at $8.53/dry-ton; 60 million tons of biomass are located beyond 75 miles and could be delivered at $36/dry-ton.     

Mergers and acquisitions in aviation – Management and economic perspectives on the size of airlines

This paper reviews literature and management perspectives on airline mergers and acquisitions. We find that M&A/consolidation is seen as a “game-changer” and mandatory to survive in aviation markets. We, therefore, apply DEA models to 66 airlines to evaluate whether big is indeed always beautiful. Our results suggest that the optimal airline size is between 34 and 52 bn available seat kilometre capacity and that airlines with more than 200 bn ASK are definitely too large to operate efficiently. This also applies when revenues are included in the DEA models, which is central as yield management and ancillary revenues are increasingly important.     

Impacts of vehicle restrictions on urban transport flows: The case of Santiago,Chile

Regression models are employed to quantify the effects of vehicle restrictions on private and public transport passenger flows in Santiago, Chile using trip flow data for cars, buses and the city's Metro rail system. Estimates are derived for the effects of two restrictions: a permanent measure applied from April through August 2008 to vehicles without catalytic converters and additional measures that banned the use of vehicles with catalytic converters between 7:30 am and 9 pm on days declared as environmental “pre-emergencies” due to high air pollution levels. The estimates show that the permanent restriction had no impact on the use of private cars while the additional restriction curtailed their use by 5.5%. Also, on pre-emergency days the flow of passengers to the Metro increased by about 3% while the bus network showed no statistically significant increase. The pre-emergency restrictions thus had an effect on the ridership of the Metro but not on the bus network as alternatives to the use of private cars.     

The effects of road infrastructure improvement on work travel in Northern Iceland

Work travel is an important alternative to out-migration in rural areas characterized by a limited range of jobs. The size of local labour markets is determined in part by geography and tradition, but advances in transportation have the potential to move people and communities closer together and transform established mindscapes. In Iceland, the dispersion of the rural population, a challenging terrain, and unpredictable weather has made road infrastructure improvements a key component in regional development strategies. A large-scale tunnel project completed in 2010 was intended to strengthen a vulnerable rural area on the northern coast and expand the urban labour market of the regional centre of Akureyri. Traffic surveys and resident surveys conducted before and after the tunnels show a substantial increase in 17–34 km work travel between rural communities. Work travel 61–77 km to and from the regional centre did however not increase. The average length of work travel has shortened but the increase in commuting yielded a net increase in total km commuted. The tunnels increased work travel irrespective of age and education, but increased work travel by women with children in the household in particular. The results suggest that large-scale road infrastructure improvements may substantially strengthen rural labour markets within a driving distance of 15–30 min, but may not extend the edge of micropolitan labour markets 45–60 min from an urban centre of less than 20 thousand inhabitants.     

Cyclists' exposure to air pollution and road traffic noise in central city neighbourhoods of Montreal

It is well known that bicycling in urban areas has beneficial effects on people's health and well-being. On the other hand, urban cycling, especially during the morning and evening commute, may be associated with health and safety risks due to potentially high levels of exposure to air pollution, road noise, and high traffic density. Few studies have, however, measured cyclists' exposure to noise and air pollution simultaneously.The objective of this research is to evaluate cyclists' exposure to air pollution and noise in central city neighbourhoods of Montreal and to identify the impact on exposure of associated local factors such as weather conditions, the day and time, the type of road, bicycle path or lane used and the characteristics of the immediate environment around the cyclist's route.A total of 85 bicycle trips were analyzed, representing 422 km of travel and nearly 25 h of data collection. The mean exposure levels were 70.5 dB(A) for noise and 76 μg/m³ for nitrogen dioxide (NO₂). A very weak negative correlation was found between the two measures of exposure (R² = − 0.07, p = 0.005).The results of the spatial regression models show that the morning commute and trips on collector roads and on-street bike lanes and shared bike lanes have significant and positive impacts on exposure to air pollution and noise. On the other hand, some factors are only significant for one or the other of the two types of exposure.     

Impacts on accessibility of China’s present and future HSR network

Although the construction of China’s high-speed rail (HSR) network only started in 2003, the network is already the largest in the world. This paper analyses the impact of the evolving HSR network on the accessibility by HSR and conventional ground transport of 333 prefecture-level cities and 4 municipalities. This paper employs three indicators of accessibility, and analyses three Scenarios. It shows that the HSR network will bring about substantial improvement in accessibility, and lead to national time–space convergence, but will also increase the inequality of nodal accessibility between eastern, central, and western regions, between cities with different sizes of population (excluding the case of the daily accessibility indicator) and between cities that differ in the shortest distance to HSR stations. The HSR network enlarges internal disparities in each of the regions and the five types of cities. The internal inequality of nodal accessibility in all three Scenarios generally increases from the eastern region via the central region to the western region, as well as from very large cities to small cities, varying inversely with the level of economic development and population size. Spatially, accessibility increases generally conform to the distance decay rule but with minor fluctuations. The 50 cities with the largest increases in accessibility are mostly located 50 km or less away from HSR stations and have populations of over 3 million, with the smaller ones located along HSR lines or around large cities such as Beijing, Shanghai, and Guangzhou. As time progresses, the planned HSR network will result in more balanced development, but regional disparities in accessibility will still be greater than before the construction of the HSR.     

Design speeds and acceleration characteristics of bicycle traffic for use in planning,design and appraisal

This paper reports the results of a study of a cohort of cyclists to determine their speed and acceleration characteristics relative to gradient and other influencing factors in order to supply data for planners, designers and appraisers of cycle infrastructure schemes. A cohort of everyday cyclists was supplied with a global positioning system device and a heart rate monitor and asked to collect data from their journeys in Leeds, UK.The analysis determines the cyclists’ speeds and accelerations at every point on their journey and elevation data, corroborated by mapping information, was used to determine the gradient. Two linear regression models of speed and acceleration were estimated and show that the influence of a downhill gradient on speed is less pronounced than the effect of an uphill gradient. The results indicate an eighty-fifth percentile speed on the flat of 22 kph, and for a downhill gradient of 3%, 25 kph. The power required to cycle has been estimated and shows that cyclists deliver around 150 W on the flat, but that this rises to around 250 W climbing hills. Mean acceleration on the flat is 0.231 m/s² and the average power output over the acceleration phase, which is of mean duration 26 s, is approximately 120 W. Air resistance accounts for approximately 70% of the resistive force when cycling at design speed.It is recommended that designers adopt 25 kph as a design speed for gradients less than 3%, but that consideration should be given to design speeds of up to 35 kph for steeper gradients. Free-flow speeds in this range should be used when modelling mode and route choices and in benefit appraisal.     

Exploring heterogeneity in travel time expenditure of aging populations in the Netherlands: results of a CHAID analysis

The aim of this paper is to contribute to the increasing literature on travel behavior and time use of the elderly. The Dutch National Travel Survey, administered in 2009, was used as a data source. First, various facets of activity-travel patterns of the elderly were compared against overall sample averages. Results indicate that the new generation of elderly people do not differ that much from other age groups in terms of their activity-travel behavior. Differences in behavior can be largely understood in terms of constraints acting on agendas. Moreover, travel patterns of elderly are affected by socio-demographic variables. Second, to further qualify the average findings, the Chi-square automatic interaction detection (CHAID) method was applied to explore heterogeneity among the elderly in terms of travel time expenditure. It is analyzed how differences in travel time co-vary with socio-demographics, in addition to activity type, activity duration and travel aspects. The results suggest that the aging population can be systematically broken down into several homogeneous cohort segments. Travel time of elderly groups depends significantly on transport modes, travel motivation, and seven socio-demographic variables (gender, age, living environment, personal net-income, household size and season). Moreover, there is less heterogeneity in travel time of elderly who are older than 75 years old. However, for younger elderly people, especially the group aged from 65 to 74 years old, heterogeneity affects their travel.     

Complaints caused by aircraft operations: an assessment of annoyance by noise level and time of day

The impact of aircraft movements on the local community surrounding an international airport was investigated using airport data on complaints, noise monitoring, aircraft flight paths and movements to assess annoyance due to noise level and time-of-day. As predicted, the louder the noise the more complaints were generated, with twice the complaints per movement at 110–114 PNdB compared with 74–79 PNdB.The hourly patterns in flight frequency and complaints were clearly distinct. Calculations of the complaints per aircraft movement for each hour of the day showed a striking 24 h pattern with night flights (23.00–06.00) causing on average nearly five times more complaints than the rest of the day (06.00–23.00). The time of the greatest propensity to complain about aircraft noise was between 01.00 and 02.00 and the lowest between 08.00 and 09.00.The circadian pattern in sensitivity to aircraft noise could be used to inform the development of airport operations and flight movements to minimize community disturbance.     

Does the built environment make a difference? Additional evidence from the daily activity and travel behavior of homemakers living in New York City and suburbs

Homemakers, unlike employed people who have jobs and unemployed people who are seeking jobs, are a special group who do not have to spend time working out of the home, commuting to work, or looking for a job. Given that a regular job typically takes 9 h (This includes an assumed half-hour one-way commute time.) a day, the discretion to allocate their time is presumably much greater than other groups.In this paper, we focus our attention on homemakers’ activity and travel behavior in neighborhoods with different characteristics (e.g., very dense areas, dense areas, and suburbs). The question to be answered is quite simple: are there differences between travel behaviors of homemakers living in different types of neighborhoods? If yes, can these differences be attributed to differences in the built environment?The dataset used in the study is the Household Interview Survey (HIS) collected in 1997/1998 in the New York metropolitan area. We found significant differences in activity and travel related behavior by homemakers living in different types of neighborhoods. Compared to suburban homemakers, New York City homemakers spend more time on discretionary activities and less time on maintenance activities; use public transportation and walk more frequently; and conduct fewer trip chains. The study found that both individuals’ socio-economic characteristics and built environment appear to play a role in explaining behavior. A probably more important factor in explaining people’s time use behavior is the interrelationship between activities and trips, and between different types of activities.     

Active-transport walking behavior: destinations,durations, distances

This paper fills a gap in our knowledge of active-transport (AT) walking, by presenting detailed aspects of walking behavior for a medium-sized North American city. It analyzes the frequency and length of walking episodes, categorized by origins, purposes, and destinations, and also investigates distance-decay functions for major destinations. The study employs day-after recall time diary and questionnaire data from the 2007–8 Space–Time Activity Research (STAR) survey conducted in Halifax, Canada. GPS co-ordinate data enhanced the accuracy of location information, start times, and end times of the 1790 AT walking episodes, while GIS software was used to compute a shortest-path distance between the origin and destination of each episode.Home is both the most common origin and destination for AT walks, and the most common purpose is travel-to-shop rather than travel-to-work. Most walks are to non-home locations, such as retail establishments and offices. Particularly important are restaurants and bars, grocery stores, shopping centers, banks, and other services. All major destinations show strong distance-decay effects: most walks are shorter than 600 m, and very few exceed 1200 m. The assumption employed in the walkability literature, that one should restrict the ‘neighborhood of opportunity’ to walking destinations within 1000 m of the home, is seen to be well justified. However, a planning policy focus on the walker’s home neighborhood is revealed as questionable, since the majority of walking trips do not originate from the home. The relationship between urban land-use patterns and walkability may therefore require some rethinking.     

Exploring the relationship between multilevel highway networks and local development patterns—a case study of Taiwan

The relationship between local development patterns and highway networks is complicated, as suggested by studies using various analytical methods. The spatial effects of each hierarchical highway network on local development patterns remains unclear. This study combines space syntax and the hierarchical linear model (HLM) within the research framework in a case study of Taiwan. The former is employed to model the topological accessibility of multilevel highway networks, and the latter is applied to handle the hierarchical relationship between multilevel highway networks and local development patterns. Results indicate a high R-squared (R² = 0.803) value, and statistically significant cross-level interactions are observed. The results show the different spatial effects of various highway networks on the scale of local development patterns, and confirm consideration of highway networks with classification in the research design. The implications of the findings may be appropriate for substantive planning and future research approaches.     

Ride-sourcing compared to its public-transit alternative using big trip data

Ride-sourcing risks increasing GHG emissions by replacing public transit (PT) for some trips therefore, understanding the relation of ride-sourcing to PT in urban mobility is crucial. This study explores the competition between ride-sourcing and PT through the lens of big data analysis. This research uses 4.3 million ride-sourcing trip records collected from Chengdu, China over a month, dividing these into two categories, transit-competing (48.2%) and non-transit-competing (51.8%). Here, a ride-sourcing trip is labelled transit-competing if and only if it occurs during the day and there is a PT alternative such that the walking distance associated with it is less than 800 m for access and egress alike. We construct a glass-box model to characterise the two ride-sourcing trip categories based on trip attributes and the built environment from the enriched trip data. This study provides a good overview of not only the main factors affecting the relationship between ride-sourcing and PT, but also the interactions between those factors. The built environment, as characterised by points of interest (POIs) and transit-stop density, is the most important aspect followed by travel time, number of transfers, weather, and a series of interactions between them. Competition is more likely to arise if: (1) the travel time by ride-sourcing <15 min or the travel time by PT is disproportionately longer than ride-sourcing; (2) the PT alternative requires multiple transfers, especially for the trips happening within the transition area between the central city and the outskirts; (3) the weather is good; (4) land use is high-density and high-diversity; (5) transit access is good, especially for the areas featuring a large number of business and much real estate. Based on the main findings, we discuss a few recommendations for transport planning and policymaking.     

Mapping bicycle use and the risk of accidents for commuters who cycle to work in Belgium

This paper explores the spatial patterns of bicycle use for commuting and the risk cyclists run being injured in a road accident when commuting to work in Belgium. Exploratory data analyses suggest that the observed differences in the use of the bicycle to get to work are strongly linked to the urban hierarchy: commuters are more inclined to cycle in cities and specifically in regional towns (with 25 000 to 120 000 inhabitants). In large cities (more than 200 000 inhabitants), less commuting by bicycle takes place. The relationship between bicycle use and the risk of being seriously injured or killed in a road accident is also studied. A cluster analysis confirms that high proportions of commuter cyclists are correlated with low risks of becoming a casualty. It also shows that there are strong spatial differences (regional and between different types of towns) in bicycle use and the risk of an accident. This suggests that cycling policies should be spatially differentiated.     

Continuity and change in American urban freeway networks

The American Interstate Highway System was created in 1944, though construction did not commence until 1956. During the planning process for this network the blueprint for American urban freeway systems was set in 1955 by a federal document called the Yellow Book. This provided about 100 maps of cities with planned urban freeway locations for the Interstate Highway System. A set of three basic network patterns were applied to these cities based on their size and location. In the half century since 1955 urban freeways in the Interstate System have expanded from a planned 2000 miles to over 16,600 miles, along with another 11,500 miles of non-Interstate freeways. The number of large metropolitan areas has increased tremendously while the monocentric commuting patterns of have been transformed. This paper explores how these urban freeway systems were applied to the country's urban geography of the 1950s and how they have adapted to changing populations and other transformations in American metropolitan areas in the last half century.     

School site walkability and active school transport – association,mediation and moderation

Increasing active school transport (AST) can improve population health, but its association with the urban form is not fully clear. This study investigated the association of an objective school walkability index with AST and how this association is mediated by the perceived physical and social environment. 1250 Danish students aged 11–13 years completed a commuting diary and a questionnaire. The walkability index was constituted of measures of road connectivity, traffic exposure and residential density. AST’s share in all school trips was 85.4% with little difference between genders. The school walkability index was significantly associated with AST (Medium vs. Low OR 2.68; High vs. Low OR 2.49). Adding the perceived physical and social environment variables improved the model prediction of AST, with no change in the association with the school walkability index. Furthermore, distance to school significantly moderated the association between the school walkability index and AST. This research confirms the association between the urban form surrounding schools and AST. Medium and highly walkable school sites in combination with a distance to school below 2 km, no speeding traffic and many paths in the neighborhood was associated with the highest odds ratio for AST.     

Multivariate analysis of the impacts of NAS investments: A case study of a capacity expansion at Dallas-Fort Worth Airport

Multivariate statistical analysis is used to estimate the impacts of a major capacity expansion at Dallas-Fort Worth International Airport. The model relates the Daily Flight Time Index (DFTI) to demand, weather, origin airport congestion, and the expansion itself. The effect of the capacity expansion on DFTI is found to depend strongly on visibility. On average, the index in the post-expansion period is 1.3 min less as a consequence of investment. This change includes a larger reduction in departure delay that is offset by an increase in taxi time. Moreover, the reduction caused by the expansion has been more than offset by increases in the DFTI resulting from other factors, notably increased demand and worse weather.