PM,NOx and CO2 emission reductions from speed management policies in Europe

Speed reduction measures rank among the most common schemes to improve traffic safety. Recently many urban streets or entire districts were converted into 30 kph zones and in many European countries the maximum permissible speed of trucks on motorways is under discussion. However, besides contributing to traffic safety, reducing the maximum speed is also seen as beneficial to the environment due to the associated reduced fuel consumption and lower emissions. These claims however are often unsubstantiated.To gain greater insight into the impact of speed management policies on emissions, this paper examines the impact on different traffic types (urban versus highway traffic) with different modelling approaches (microscopic versus macroscopic). Emissions were calculated for specific types of vehicles with the microscopic VeTESS-tool using real-world driving cycles and compared with the results obtained using generalized Copert-like macroscopic methodologies. We analyzed the relative change in pollutants emitted before and after the implementation of a speed reduction measure for passenger cars on local roads (50–30 kph) and trucks on motorways (90–80 kph). Results indicate that emissions of most classic pollutants for the research undertaken do not rise or fall dramatically. For the passenger cars both methods indicate only minor changes to the emissions of NO_x and CO₂. For PM, the macroscopic approach predicts a moderate increase in emissions whereas microscopic results indicate a significant decrease. The effects of specific speed reduction schemes on PM emissions from trucks are ambiguous but lower maximums speed for trucks consistently result in lower emissions of CO₂ and lower fuel consumption. These results illustrate the scientific uncertainties that policy makers face when considering the implementation of speed management policies.     

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.     

An international comparison of the self-reported causes of cyclist stress using quasi-naturalistic cycling

This study explores the influences of attitudes and setting on cyclists' stated causes of stress using survey techniques and quasi-naturalistic cycling in both Delft, The Netherlands and Atlanta, Georgia, USA. The study recruited 28 participants in Delft and 41 in Atlanta. Participants cycled approximately 30 min on specified routes in both cities on an instrumented bicycle. Prior to cycling, the participants filled in a written survey about their cycling habits, attitudes, and demographics. At specified points during and after the ride, participants were interviewed about their stress levels throughout the ride and the causes of those stress levels. Thematic analysis and statistical methods are used to understand the interactions of setting (country), attitudes, stated stress, and sensor data. The top three stressors were motor vehicles, pavement, and poor infrastructure; 83% of participants mentioned a motor vehicle causing stress, 64% mentioned road surface, and 58% mentioned infrastructure. The results confirm the importance of motor vehicle interaction to cyclist stress, but also highlight some new insights on stress such as the importance of pavement condition. Speed differentials between cyclists and vehicles were also shown to be important and suggested cyclists in Delft felt comfortable to travel their ideal speed. This speed preference was supported by GPS data that showed the cyclists in Delft were cycling at speeds about half (12 kph) that of the cyclists in Atlanta (24 kph). Review of close-pass events demonstrated that cyclists in Delft were more comfortable with closer passes which could be associated with their belief that motorists notice them and/or speed differences between the vehicle and bicycle. The results also suggest that number of vehicle travel lanes can have mixed impacts on cyclist stress. These findings can be taken into consideration when designing bicycle facilities to create low-stress cycling networks.     

Methods for deriving and calibrating privacy-preserving heat maps from mobile sports tracking application data

Utilization of movement data from mobile sports tracking applications is affected by its inherent biases and sensitivity, which need to be understood when developing value-added services for, e.g., application users and city planners. We have developed a method for generating a privacy-preserving heat map with user diversity (ppDIV), in which the density of trajectories, as well as the diversity of users, is taken into account, thus preventing the bias effects caused by participation inequality. The method is applied to public cycling workouts and compared with privacy-preserving kernel density estimation (ppKDE) focusing only on the density of the recorded trajectories and privacy-preserving user count calculation (ppUCC), which is similar to the quadrat-count of individual application users. An awareness of privacy was introduced to all methods as a data pre-processing step following the principle of k-Anonymity. Calibration results for our heat maps using bicycle counting data gathered by the city of Helsinki are good (R² > 0.7) and raise high expectations for utilizing heat maps in a city planning context. This is further supported by the diurnal distribution of the workouts indicating that, in addition to sports-oriented cyclists, many utilitarian cyclists are tracking their commutes. However, sports tracking data can only enrich official in-situ counts with its high spatio-temporal resolution and coverage, not replace them.     

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.     

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.     

Effects of upgrading to cycle highways - An analysis of demand induction,use patterns and satisfaction before and after

ObjectiveThe objective of the present study is to investigate the effects of improvements made to two large, interconnected bicycle infrastructure in the western suburbs of Copenhagen, Denmark, on bicycle volumes and mode share, and cyclists' behaviour, perceptions, and experiences.MethodsEffects are assessed by analysing data from automatic counting stations during 35 months to measure the changes in bicycle volumes on the investigated routes. Furthermore, a questionnaire survey repeated three times – before, and one and two years after opening the improved routes - is used. Findings are supported by a control survey at a nearby facility, which was not influenced by the infrastructure improvements.ResultsThe investments related to the two investigated cases of infrastructure improvements resulted in a significant increase in the volume of bicyclist two years after the improvements. On one of the routes, the “Albertslund Route”, on weekdays during the rush hour in daylight, an increase from 126 to 203 bicyclists/h was recorded, whereas an increase from 24 to 32 bicyclists/h was recorded at “Vestvolden” for the same period. Most of the increase could be attributed to relocation of bicyclists from other routes. Induced cycling trips – trips that were not previously made by bicycle - were estimated to account for only 4–5% of the bicyclists two years after improvements. Bicyclists using the improved route express an increase in satisfaction with the quality of the facilities, which is significantly higher than at the control site.ConclusionData from the counting stations provides useful information if measured over a long period. This is necessary to correct for factors such as climate effects and temporal variation. Investments in cycle infrastructure in the investigated case led to a higher number of bicyclists who were mainly relocated from other routes. A minor increase in the modal share of cyclists was observed two years after the infrastructure improvements. Furthermore, the investments resulted in a higher degree of satisfaction among active bicyclists. If measured over a longer period, this could lead to a higher modal share due to a potential social advertising effect.     

Development and test of the Perceived Accessibility Scale (PAC) in public transport

Perceived accessibility, defined as “how easy it is to live a satisfactory life using the transport system”, is proposed to be a complementary measure to conventional, objective measures of accessibility. Aiming at capturing the subjective element of accessibility, as opposed to conventional accessibility that is based on the same objective attributes for large areas or groups of people, the authors developed and tested a measure of perceived accessibility; the four items self-reported Perceived Accessibility Scale (PAC). In study 1, 237 users of public transport rated PAC. The results showed that PAC is a reliable measure. The PAC was further validated and proved reliable in two waves (study 2) in altered conditions (Wave 1, N = 246, Wave 2, N = 259). Based on this, an overall PAC index was constructed. PAC can be used to determine the traveler's (or possible travelers) opinion of accessibility in transport planning or accessibility-mapping, or for directing interventions aimed at improving accessibility to where they are best needed according to the individuals. Further development of the PAC and its potential within transport research and planning, and its future validation is discussed.     

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.     

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.     

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.     

Spatial interpolation of traffic counts based on origin–destination centrality

This paper presents a new method to estimate Annual Average Daily Traffic. Often traffic volumes are estimated based on roadway characteristics, such as number of lanes, speed limit, and adjacent land use. However, for many communities, especially small communities, these attributes are uniform across roadway types and therefore unable to adequately explain observed variation in traffic volumes. The new method uses novel explanatory variables that are intrinsically derived through a modified form of centrality, a network analysis metric that quantifies the topological importance of a link in a network. The new approach requires minimal data collection and is easily executed using a geographic information system. The case study showed high quality results (out-of-sample validation R² = 0.95). The new approach can be used for various activities related to transportation planning and investment decision making.     

How children view their travel behaviour: a case study from Flanders (Belgium)

Understanding the thoughts of contemporary children about travel and their opinions on different transport modes of transport may provide important answers for policy-makers on how to respond to current and future transport needs of children. Obviously, children do not act autonomously and their travel behaviours also strongly influence their parents’ travel behaviours. Therefore, a better understanding of children’s travel behaviours seems necessary.This paper reports the results of a large-scale, self-reporting survey (N = 2546) that was conducted to examine the concept and meaning of travel and travel behaviour of children aged between 10 and 13 years in Flanders. It was found that children are able to complete a travel diary on their own, that their travel patterns differ and that the most important part of travelling for them is the social aspect.     

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.     

Ex-post environmental and traffic assessment of a speed reduction strategy in Madrid's inner ring-road

Since urban traffic is a major source of CO₂ and NO_x emissions, cities play a key role averting climate change and combating air pollution. Most researchers agree on the need of designing comprehensive mitigation strategies instead of applying isolated measures. Nevertheless, it is important to understand the specific impact and scope of each measure to look for the most effective synergies among them. In 2004, the Madrid City Council launched a plan to re-design its inner ring-road to move traffic out of the city centre. For safety reasons the planned speed limit for the full-renovated South-West section was finally reduced from 90 km/h to 70 km/h. Besides contributing to traffic safety, this strategy could also be seen as positive to the environment due to the associated reduced fuel consumption and lower emissions. However, lower speed limits have lower rates of community acceptance due to its impact on average travel times at the individual level. This paper conducts an ex-post evaluation of this speed reduction strategy to explore its environmental and traffic performance impacts. The results support the thesis that, in this velocity range, lower speed limits present important opportunities for reducing GHG and air pollution in the section affected by the measure, without substantially altering traffic performance. The implementation of the new speed limit policy produces a 14.4% and 16.4% reduction in CO₂ and NO_x emissions respectively, while global travel time remains virtually constant and the saturation rate decreases slightly. Besides, this cost-effective measure reveals great potential to reduce air pollution in highly populated urban areas located next to urban highways. This work provides local policy makers and city managers with useful insights regarding potential co-benefits of traffic optimization and speed reduction management to reduce mobile source emissions in urban environments.     

Future mobility in India: Implications for energy demand and CO2 emission

The aim of this study is threefold. First, it aims to provide a reliable data set of land-based passenger traffic volumes in India from 1950–1951 to 2000–2001 for the five major motorized modes of transport—two-wheelers, cars, auto-rickshaws, buses, and railways. Second, based on this data set, it aims to estimate the long-term trends in motorized traffic volume and modal split up to the year 2020–2021. Third, based on the projected values of aggregate traffic volume and modal split, this study aims to estimate the level and growth of energy demand and CO₂ emission from the passenger transport sector in India. It is found that the motorized traffic volume in India will very nearly touch the mark of 13 000 billion passenger-kilometers in 2020–2021, out of which 91.7% will be provided by the roads and the rest by railways. If there is no reduction in modal energy and CO₂ intensities, energy demand is projected to increase from 1060.8 peta joules in 2000–2001 to 5584.4 peta joules in 2020–2021 and CO₂ emission will increase from 19.80 to 93.25 million metric tons of carbon equivalent during the same period.     

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.     

Relationships between commuting distance,frequency and telework in Finland

The average commuting distance in Finland has increased steadily during recent decades. Daily long-distance commuting especially increases the number of vehicle-kilometres travelled. The aim of this work was to determine the relationship between commuting distance and frequency. The focus was on direct impacts of telework on commuting, but the significance of second apartments close to the workplace was also estimated. The empirical analyses were based on aggregate national data concerning commuting distances and a survey providing data of 19 000 employed respondents. The results of the study indicated that telework reduced by 0.7% the total kilometres travelled in Finland. The probability of working at home increases with commuting distance, but when the commuting trip exceeds 100 km a second apartment near the workplace becomes common and has a stronger impact on commuting kilometres travelled than telework.     

Policy clash: Can projected aviation growth be reconciled with the UK Government's 60% carbon-reduction target?

In 2004, the UK's aviation industry emitted an estimated 9.8 MtC; a figure that, without direct intervention, is projected to rise to 16–21 MtC by 2030 according to the UK Government. As the UK's 60% carbon-reduction target approaches, so aviation is likely to become a dominant carbon-emitting sector. This paper calculates the proportion of carbon emissions resulting from the Government's projected aviation growth in relation to a contracting carbon budget. It concludes that the Government must urgently address today's very high levels of growth in emissions within the industry, and ensure future growth can be reconciled with the Government's own carbon targets.     

Bus rapid transit impacts on land uses and land values in Seoul,Korea

Bus rapid transit (BRT) has gained popularity as a cost-effective alternative to urban rail investments; however, relatively little is known about its impacts on land-use changes and land values. This paper examines the land-market effects of converting regular bus operations to median-lane bus services in Seoul, Korea, one of the densest, most congested cities in the world. Multilevel models reveal BRT improvements prompted property owners to convert single-family residences to higher density apartments and condominiums. Land price premiums of up to 10% were estimated for residences within 300 m of BRT stops and more than 25% for retail and other non-residential uses over a smaller impact zone of 150 m. The research findings underscore the importance of introducing zoning and other land regulatory changes prior to the initiation of BRT improvements as well as applying value-capture tools to help finance investments and redress inequities.