TØI Vitenarkiv
Not a member yet
668 research outputs found
Sort by
The limits of soft safety regulation: Does successful work with safety culture require SMS implementation?
Get PDFPublished by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).The Swedish Transport Agency defined contributing to a high safety culture in transport companies as a key element in its regulatory strategy. This study examines how the safety culture strategy was received and enacted by regulators and companies within each transport sector, and factors influencing this. We discuss what a regulatory agency can accomplish through a safety culture strategy, and the extent to which it is bounded by the safety management maturity level in each sector. A key question is whether safety management requires a sequential, or evolutionary development, where companies must implement well-functioning safety management systems (SMS) before being organisationally mature enough to work successfully with safety culture. Our results seem to support this assertion, as we find that transport sectors with legal SMS requirements focus on safety culture, and work with safety culture elements (e.g. reporting/just culture, continuous improvement, involvement) to ensure that the SMS is a living system. Sectors without SMS requirements (i.e. road) do not focus on safety culture. Without SMS, it seems that safety culture work equals focusing on safety commitment among managers and employees. We identify additional factors influencing organisational maturity level and safety culture focus, limiting soft safety regulation, e.g. business structure, maintaining equal conditions for competition.The limits of soft safety regulation: Does successful work with safety culture require SMS implementation?publishedVersio
Agglomeration decay in rural areas
Get PDFHolmen, R. B. 2022. Agglomeration decay in rural areas, Insights into Regional Development 4(3): 139-155. https://doi.org/10.9770/IRD.2022.4.3(9)Spatial proximity to other economic activities – occasionally labeled as ‘market access’ and ‘economic density’ – is associated with good economic performance. How the impulses from economic activities diminish over space is known as ‘agglomeration decay’ or ‘distance decay’. Although market access functions and the associated agglomeration decay constitute an important topic within spatial economic research, the phenomenon is seldom studies in a rural setting or addressed by non-linear estimation techniques. In this paper, we estimate the market access function in the relatively rural regions of Southern parts of Norway. We approximate market access in the national road network by alternative market access functions with power and exponential distance decay, applying ordinary non-linear least squares (NLS) and non-linear mixed effects (NLME). We apply labor productivity as the outcome variable, employment and population as alternative measures for potential market connections and traveling time as distance measure. In the regression, we control for capital intensity, industry structure and annual growth trend, as well as mixed effect in case of the NLME model. Compared to previous findings in the literature, we find evidence of relative sharp agglomeration decay in a rural setting, involving power and exponential distance decay parameters of about 2.3 and 0.07 respectively. Comparisons of the log likelihood from the estimation of market access functions suggest that exponential distance decay involve a slightly better fit than power distance decay. In addition, employment involves slightly more explanatory power than population as a measure for potential market connections.Agglomeration decay in rural areaspublishedVersio
Quantification of temperature dependence of NOx emissions from road traffic in Norway using air quality modelling and monitoring data
No full textPublished by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)Emissions of nitrogen oxides (NOx) from road traffic are dependent on a range of factors including vehicle type, speed, driving patterns and engine temperature. Recently a number of studies have indicated that ambient air temperature plays an important role in vehicle NOx emissions, mainly due to various technical challenges of diesel vehicles that occur at low ambient temperatures. This study aims to derive a correction formula to account for this temperature dependence when calculating emissions from road traffic in Norway. Measured NOx concentrations in the period 2016–2019 at 46 sites dominated by road traffic sources are compared to the NOx concentrations calculated with the chemistry-transport modelling system EMEP/uEMEP at the same sites. The model has good road traffic volume input data, but no temperature dependence in the emission factors. A clear temperature dependence in the observed-to-modelled ratio of NOx concentration is found. The ratio increases from 1.09 at high temperatures to 2.9 at low temperatures. The increase occurs gradually in the temperature range from -13 °C to +14 °C. Assuming this temperature dependence in the bias is due to the road traffic emissions, a correction formula for these emissions is derived. The correction factor is 1 at high temperatures and 3.28 at low temperatures, with a linear increase in the range from +12.4 °C to -12.9 °C. Thus, our results suggest that road traffic emissions should be 3.3 times higher at temperatures below -13 °C than at high temperatures, and 2.7 times higher at -7 °C. The temperature range and magnitude of this temperature dependence are consistent with the existing literature on emission measurement experiments performed on various models of diesel vehicles. The derived temperature dependence can be used to correct road traffic emissions. However, the parameter values in the correction are dependent on the vehicle fleet composition and are applicable only for the current Norwegian vehicle fleet.publishedVersio
Driver mileage and accident involvement: A synthesis of evidence
Get PDFThis is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).The relationship between driver mileage and accident involvement has been a controversial topic for at least 20
years. The key issue is whether driver accident involvement rate increases in proportion to miles driven or has a
non-linear relationship to miles driven. This paper presents a synthesis of evidence from studies of how the
number of accidents per driver per unit of time relates to distance driven in the same period. Most studies of this
relationship are methodologically weak and their results highly inconsistent and potentially misleading. Unre liable data and poor control for confounding factors characterise most studies. Only a few studies based on
multivariate statistical models control for at least some of the confounding factors that may influence the
relationship between distance driven and accident involvement. These studies consistently show that the number
of accidents per driver per year increases less than in proportion to distance driven. A good approximation is that
the number of accidents per driver per unit of time is proportional to the square root of distance driven. Potential
methodological and substantive explanations of this finding are discussed.publishedVersio
Which is the more important for road safety— road design or driver behavioural adaptation?
Get PDFElvik, R. (2022). Which is the more important for road safety—road design or driver behavioural adaptation?. Traffic Safety Research, 2, 000009.Studies consistently show that sharp horizontal curves increase accident rate. One would therefore expect roads with many sharp curves to have a higher accident rate than roads with few sharp curves. This is not the case. The differences in road safety between roads with different profiles of horizontal road alignment are quite small. There are even studies suggesting that areas having roads with many curves have a lower number of accidents than otherwise identical areas with less curvy roads. The question arises: How can it be true both that sharp curves increase accident rate and that areas with roads with many sharp curves do not have a higher accident rate than areas with less demanding alignment? The answer is likely to be found in behavioural adaptation among drivers. The accident rates both in curves and on straight sections are strongly influenced by how drivers adapt behaviour to the number of curves per kilometre of road. This paper shows how behavioural adaptation can be quantified by means of the ‘human feedback parameter’ proposed by Evans. This parameter takes a value of -1 if drivers adapt behaviour so as to completely eliminate a risk factor. Values close to -0.7 for horizontal curves were estimated on the basis of micro-level studies. Thus behavioural adaptation reduces the increase in risk to about 30% of what it would have been without behavioural adaptation. In addition, a high frequency of curves leads to lower speed on the straight sections between curves.publishedVersio
Descriptive analysis of reports on autonomous vehicle collisions in California: January 2021–June 2022
Get PDFPokorny, P., & Høye, A. (2022). Descriptive analysis of reports on autonomous vehicle collisions in California: January 2021–June 2022. Traffic Safety Research, 2, 000011.The characteristics of autonomous vehicles’ collisions from 2021 and the first half of 2022 in California confirm trends reported in previous years. Driving in autonomous mode was associated with fewer instances in which the AV was deemed to be at fault in a collision. Most collisions in autonomous mode were rear-end collisions at intersections. Single vehicle collisions occurred mostly in manual mode. Collisions with vulnerable road users occurred mostly while the autonomous vehicle was in manual mode, often right after disengagement from autonomous mode. In collisions with other vehicles that occurred after disengagement, the other vehicles were frequently deemed to be at fault. Compared to 2021, the collision reports from the first half of 2022 indicate higher shares of collisions in autonomous mode, rear-end collisions, and collisions with vulnerable road users.publishedVersio
The engagement of informal volunteers in disaster management in Europe
Get PDFOliver Nahkur, Kati Orru, Sten Hansson, Pirjo Jukarainen, Miia Myllylä, Marco Krüger, Matthias Max, Lucia Savadori, Tor-Olav Nævestad, Sunniva Frislid Meyer, Abriel Schieffelers, Alexandra Olson, Gabriella Lovasz, Mark Rhinard, The engagement of informal volunteers in disaster management in Europe, International Journal of Disaster Risk Reduction, Volume 83, 2022, 103413, ISSN 2212-4209, https://doi.org/10.1016/j.ijdrr.2022.103413. (https://www.sciencedirect.com/science/article/pii/S221242092200632X)Informal volunteering is increasingly important in disaster management, but authorities remain cautious about collaborating with informal volunteers. Relatively little is known about the extent to which informal volunteers are integrated into European disaster management systems. We try to remedy this gap by examining Germany, Italy, Belgium, Hungary, Sweden, Norway, Finland, and Estonia, focusing on (1) the policies and institutional arrangements for integrating informal volunteers, (2) the methods and tools used for their engagement, and (3) the presumed benefits and challenges of involving volunteers in disaster management. 95 expert interviews combined with desk research and four online table-top exercises in 2019–2020 involving analysis of 11 disaster cases show that disaster management systems in these countries are taking modest steps toward opening traditional command-and-control structures to informal volunteers. In Sweden and Norway, where volunteering is more common, the engagement of informal volunteers is somewhat regulated, providing an opportunity to formally insure them. In Belgium and Italy, the engagement of informal volunteers is not encouraged, but formal volunteering is encouraged. In Germany, Hungary, Finland, and Estonia, it is done on an ad hoc basis. In most of the countries studied, campaigns to raise volunteers’ awareness of support possibilities are backed up by practical training that focuses primarily on first aid. In all countries, except Germany, social media has been used by disaster management authorities to inform, guide, or register informal volunteers on an ad hoc basis. The studied cases indicate that disaster response is more efficient when procedures for informal volunteer engagement exist.publishedVersio
Use of GPS-data to improve transport solutions in a cost and environmental perspective
Get PDFPublished by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).In this paper we have utilised GPS data as a base to track truck movements and analyse transport activities. Combined with a Decision Support Tool we have investigated how different transport solutions affect the transport cost and CO2 emissions. The information gained from GPS-data helps firms such as a fruit and vegetables wholesaler to gain better insights into their transport solution and operations from a cost and environmental perspective. This also means that the current analysis remains useful for the transporting company in making strategic decisions as to when and where they should engage in other transport assignments to improve the load factors on their trucks. This paper presents that the picture the decision-makers had prior to GPS data being used was different from the real situation, and the insights gained lead to new knowledge and actions. As a result, this would contribute to greener and more cost-efficient solutions.Use of GPS-data to improve transport solutions in a cost and environmental perspectivepublishedVersio
GPS data as a basis for mapping freight vehicle activities in urban areas – A case study for seven Norwegian cities
No full textPublished by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Purpose The current paper addresses how GPS data from freight vehicles can give detailed information on freight activities in urban areas, with examples of delivery/pickup activities in seven Norwegian cities. Such information is key when planning for freight activities in urban areas– e.g. when dimensioning the capacity of loading/unloading zones. Design/methodology/approach For 2019, a dataset of 79 million GPS positions was retrieved from 1200 freight vehicles. We present a method to convert GPS data into information on freight vehicle movements, including an approach to separate delivery/pickup activities from other stop activities in urban areas. Findings The study shows that detailed information on delivery/pickup activities in urban areas may be obtained from GPS data. We find that dwell time averages differ between outer and inner-city areas and vehicle types in Norway. Practical implications Today, most studies of this type are based on data from voluntarily participating firms, resulting in sample biases. However, as almost all new heavy goods vehicles include a possibility of GPS tracking, there is a vast future potential of such data, and this study illustrates how such data can provide transport authorities/planners with information at a more detailed level than traffic counts and at a lower cost than traditional observation studies. Original/value Several studies have addressed the issue of converting GPS data to trip information and identification of stop activities. However, we find less work on how such data may provide new insights into freight vehicle movements and activities in urban areas, and, in turn, how it may contribute to improved policy making towards the goal of greener and more efficient freight transport in urban areas.GPS data as a basis for mapping freight vehicle activities in urban areas – A case study for seven Norwegian citiespublishedVersio
Interact or counteract? Behavioural observation of interactions between vulnerable road users and autonomous shuttles in Oslo, Norway
Get PDFDe Ceunynck, T., Pelssers, B., Bjørnskau, T., Aasvik, O., Fyhri, A., Laureshyn, A., Johnsson, C., Hagenzieker, M., & Martensen, H. (2022). Interact or counteract? Behavioural observation of interactions between vulnerable road users and autonomous shuttles in Oslo, Norway. Traffic Safety Research, 2, 000008. https://doi.org/10.55329/fbhr3456The current paper presents the results of behavioural observations in a field experiment with automated shuttles in Oslo, Norway. Video observations were conducted at five fixed locations along a challenging 1.2 km automated shuttle line with varying traffic conditions. Observed interactions between vulnerable road users and automated shuttles were coded using a predefined codebook, which allowed a structured quantitative analysis. The paper identified several potentially risky types of situations in which the automated shuttles did not always behave according to the traffic rules. Generally, the automated shuttles failed to give way to pedestrians at pedestrian crossings in 26%–50% of the interactions. Right-turning shuttles failed to yield to cyclists going straight in 38% of the interactions at observation Site 1 (the only location where the automated shuttle takes a right turn). In majority of same direction interactions between cyclists and automated shuttles, the interactions resulted in the cyclist overtaking the automated shuttle, usually on the left-hand side. Generally, the paper found little evidence of road users trying to bully or otherwise take advantage of the defensive driving style of the automated shuttles and identified only a limited number of interactions in which a vulnerable road user behaved ignorant or aggressive towards the automated shuttles. In addition, the paper found very little indication of temporal effects that suggest changes in the interaction patterns over time.publishedVersio