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A comprehensive and unified framework for analysing the effects on injuries of measures influencing speed
Get PDFThis paper proposes a comprehensive and unified framework for analysing the impacts on traffic injury of measures influencing speed. The key tool for analysis is a specification of the speed distribution, which in most cases closely approximates a standard normal distribution. The speed distribution can be represented, for example, by twelve intervals each comprising one half standard deviation. The exponential model of the relationship between speed and the number of injured road users is applied to estimate the expected injury rate for drivers travelling at the mean speed of any part of the distribution. The relationship between individual driver speed and accident involvement is then incorporated into the speed distribution. A speed distribution specified this way represents both the mean speed of traffic and the variation in speed-related risk between drivers. Impacts of changes in speed that can be modelled include: (1) Shifting the whole speed distribution, (2) Compressing the upper end of the speed distribution, (3) Enlarging or reducing the variance of the speed distribution, (4) Selective changes in specific regions of the speed distribution. Examples are given of how knowledge of the impacts of measures on speed can be translated into expected changes in the number of injured road users by relying on the analytic framework.acceptedVersio
An analysis of factors influencing accidents on road bridges in Norway
Get PDFFactors explaining systematic variation in the number of injury accidents on road bridges in Norway during 2010–2016 have been identified by means of negative binomial regression models. A total of 6824 bridges recording in total 1368 accidents were included. Although almost 90% of the bridges recorded zero accidents, there is no evidence of an excessive number of zeros, often referred to as “zero-inflation”. Traffic volume, stated as AADT (Annual Average Daily Traffic), was found to be the single most important factor influencing the number of accidents. It explained nearly 72% of the systematic variation in the number of accidents. The number of accidents increased less than proportionately with traffic volume, meaning that accidents per million vehicle kilometres declined with increasing traffic volume. Long bridges were found to be safer than short bridges and recently built bridges were safer than older bridges. Based on in-depth studies, a more detailed analysis of factors associated with fatal accidents was performed.An analysis of factors influencing accidents on road bridges in NorwayacceptedVersio
Workplace location, polycentricism, and car commuting
Get PDFAlthough significant strides have been made regarding the relationship between urban structure and travel, some doubt appears to be lingering concerning the impacts of polycentric urban development. For example, the debate on whether a polycentric or monocentric workplace location pattern is favorable for reducing negative environmental effects from transportation has not been entirely settled. This study intends to contribute to clearing up some of the misconceptions by focusing on the implications of spatial distribution of jobs on commuting patterns among employees within the Oslo metropolitan area. Results show a strong tendency for a higher share of car commuting among employees working in suburban workplaces. This pattern persists also for suburban workplaces located close to suburban transit nodes. The share of transit commuters shows the opposite pattern. Commuting distances also tend to increase the farther from the city center the workplace is located. These conclusions are based on cross-sectional and quasi-longitudinal survey data as well as semi-structured in-depth interviews of workers, including several interviewees who had changed their workplace locations. To our knowledge, this is the first mixed-methods study on the influence of workplace location on commuting behavior. The results raise doubt about the appropriateness of polycentric intra-metropolitan workplace development as a strategy for sustainable mobility.publishedVersio
Revealed and stated preferences for reliable commuter rail in Norway
Get PDFWe study the effect of travel time reliability on passenger demand using a rich data set on period tickets and train delays over time for commuter trips in the Oslo capital region in Norway. We estimate the relationship between delays and demand using origin-destination fixed effects, which controls for any unobserved time-invariant heterogeneity across stations. The results show a negative effect of delays on demand, but smaller than the effect implied by stated preferences. As a possible explanation for this, we consider a reverse causal relationship, where high demand causes passenger crowding which again results in more delays. Splitting the sample into trips that start at crowded stations within the city-zone and trips that do not, we find evidence indicating that crowding is biasing the estimates towards zero.publishedVersio
Safety Culture among Private and Professional Drivers in Norway and Greece: Examining the Influence of National Road Safety Culture
Get PDFWhile Norway had the lowest road mortality rate in Europe in 2017, Greece had one of the worst road safety records of all EU-27 countries. The present study investigates road safety culture (RSC) as an explanation for this discrepancy by: (1) Comparing the road safety behaviours among professional and private drivers in Norway and Greece, (2) Examining factors influencing road safety behaviours, focusing especially on national road safety culture, and (3) Examining the influence of road safety behaviours and other factors (e.g., demographic and work-related variables) on accident involvement. This is done by comparing survey answers of private car (N = 796) and professional drivers (heavy goods vehicles and buses) in Norway and Greece (N = 416). Results from qualitative interviews (N = 61) are also presented. We study safety behaviours hypothesized to vary according to nationality (e.g., aggressive violations), and behaviours hypothesized to vary according to the professional versus private driver dimension (e.g., seat belt use). A central objective is to examine whether the former safety behaviours are more similar among private and professional drivers within countries than among professional and private drivers across national samples, indicating common national road safety cultures among private and professional drivers in the respective countries. The results indicate that aggressive violations are more similar among private and professional drivers within the national samples, than across the national samples, while seat belt use seems to vary according to the professional versus private dimension. The results also indicate a relationship between aggressive violations and accident involvement, although other variables were more strongly correlated. Moreover, drivers’ safety behaviours were influenced by the behaviours that these groups ascribed to other drivers in their countries, indicating the existence of di_erent national road safety cultures. The Greek RSC was characterized by more aggression and violations than the Norwegian RSC, which seemed to be characterized by a higher level of compliance and politeness. The different RSCs may perhaps shed light on the di_erent accident records in the two countries.Safety Culture among Private and Professional Drivers in Norway and Greece: Examining the Influence of National Road Safety CulturepublishedVersio
Who are most likely to adapt their travel behaviour to changes in weather conditions? A study of weather tolerance and travel behaviour in Norway
Get PDFThis study, based on two questionnaire surveys from two cities in Norway with different climate conditions, explores to which extent weather tolerance in terms of travel behaviour – here defined as using a non-motorized vehicle despite poor weather conditions (precipitation and/or cold weather) – is related to socio-demographic factors, environmental attitudes, transport habits as well as the climate conditions (coastal/inland) of where people live. Three indicators are used to measure ‘weather tolerance’: a) Disagreement to the statement “I always drive when it rains”; b) Willingness to walk 2-3 kilometers in minus 10 degrees Celsius or more in steady snowfall (yes/no), and c) Willingness to walk 2-3 kilometer in +20 degrees Celsius or more in steady rainfall” (yes/no). The study finds that environmental attitudes and travel habits (as perceived by the respondents) are the factors most strongly related to weather tolerance, independent on how it is measured, when other factors are controlled for. The findings suggest that policy measures to change attitudes/ increase environmental awareness as well as promoting outdoor activity in general can be effective in terms of making people choose active transportation even in poor weather conditions. This might be important steps to reduce the likelihood of car use in the future, when extreme weathers are to become more likely.publishedVersio
Train Unreliability and Demand for Rail Freight Transport in Norway
No full textWe use a rich data set on long-distance freight trains in Norway to estimate the effect of variation in train unreliability over time on transport demand within a fixed-effect framework. The train services that we study carry high-value consumer goods and compete heavily with trucks. We find that if the share of substantially delayed trains increases by 10 percentage points, freight volume goes down by about 3 per cent. In contrast with evidence from passenger transport, we do not find that the demand elasticity with respect to reliability is lower than the one implied by stated preference (SP) studies.acceptedVersio
Risk of pedestrian falls in Oslo, Norway: Relation to age, gender and walking surface condition
Get PDFThe risk of pedestrian falls in Oslo, Norway, is analysed. Injury data were collected during 2016 by the municipal emergency medical clinic. A total of 6309 injured pedestrians were recorded. 6109 were injured in falls in which no other road user was involved. The risk of falling per million kilometres walked varies by age, gender and surface condition. Women have a higher risk than men. Risk has a J-shaped variation with age for both genders, being highest among the oldest. The presence of snow or ice on the walking surface is associated with more than a doubling of risk. There are few comparable previous studies of the risk of pedestrian falls. However, to the extent comparisons can be made, pedestrian risk of injury by falling is higher in Oslo than in other cities or countries. The preventability of falls is discussed.publishedVersio
Weather and daily mobility in international perspective: A cross-comparison of Dutch, Norwegian and Swedish city regions
Get PDFWith climate change, weather has emerged as an important theme in transport research and planning. Although recent studies demonstrate profound weather effects on mobility in single case study areas, international cross-comparisons are required to reveal how effects differ between cities with different transport and climate regimes. This paper provides an international cross-comparison of the simultaneous effects of weather on destination choices, distances, trip chaining, and transport modes in the urban regions of Utrecht (Netherlands), Oslo and Stavanger (Norway), and Stockholm (Sweden). Hereto, regional subsamples of national travel survey data were linked to meteorological records for the three respective countries and analysed in generalised Structural Equation Models. Our findings generally indicate that light, calm, dry and warm atmospheric conditions may positively affect cycling and the selection of outdoor leisure destinations, while cold and to a lesser extent wet and windy weather conditions reduce cycling and enhance car use and travel optimising strategies like trip chaining, to reduce weather exposures. A positive effect of air temperature on cycling flattens out above 20–25 °C in most of our study areas, but hot weather does not seem to reduce cycling strongly. However, our findings also show considerable regional differences in the effects of weather on mobility. Both general effects and differences are interpreted in relation to geographical context, transport and land use, climate conditions, cultures, habits and adaptations and are discussed to formulate policies to mitigate active transport mode users’ exposures to adverse weather and make walking and cycling (even more) year-round modes.publishedVersio