Traffic risk perception,road safety attitudes,and behaviors among road users: a comparison of Turkey and Norway

The present study aims to investigate differences in road safety attitudes, driver behavior, and traffic risk perception between Turkey and Norway. A questionnaire survey was conducted among a sample of Norwegian (n?=?247) and Turkish (n?=?213) road users. The results show that Turkish respondents perceived traffic risk to be higher than Norwegian respondents. Turkish respondents reported safer attitudes towards drinking and driving than Norwegian respondents, while Norwegians reported safer attitudes towards speeding. Turkish respondents reported a lower frequency of speeding behaviors than Norwegian respondents, whereas Norwegian respondents reported a lower frequency of drinking and driving. Traffic risk perception was related to road safety attitudes and behaviors among Norwegian respondents but not among Turkish respondents. The results were discussed with respect to differences in traffic safety, traffic culture, and the development levels in Turkey and Norway.     

A practical approach for the evaluation of acceptable risk in road tunnels

In many European countries it is common to adopt quantitative criteria in evaluation of acceptable risk in road tunnels. Such criteria, usually expressed by FN-criteria and IR-values, will easily lead to a regime that is difficult to adopt in practice, as the use of such criteria requires extensive analyses and documentation for all types of tunnels. In this paper, a more practical approach for the evaluation of acceptable risk in road tunnels is presented, in which quantitative risk acceptance criteria are used for some road tunnels, while qualitative criteria are used for others. This means that varying degrees of effort and documentation are necessary for the evaluation of acceptable risk in road tunnels. The approach suggested is inspired by challenges in Norway.     

Participatory safety barrier analysis: a case from the offshore maritime industry

This paper argues that a participatory approach directly involving employees in safety barrier analysis can provide ‘added value’ to traditional barrier analyses. Employee participation (EP) could motivate employees to use their knowledge, suggest improvement measures and express their concerns. EP has not received much attention from safety researchers, although one may find several indirect arguments for EP informing the influential safety theoretical perspectives. An example of how participatory safety barrier analysis can be completed and what can be accomplished through such an approach is illustrated via a case study from an offshore logistics chain, and by an analysis of barriers that should prevent collisions between supply vessels and offshore installations. Such collisions could be the initiating event for a major accident. The empirical foundation for the paper is a hazard identification technique session, group and individual interviews, document studies and two search conferences involving approximately 150 participants. It is argued that a participatory approach to safety barrier analysis can reveal ‘holes’ in the defences that otherwise could have gone overlooked, and contribute to the generation of contextualized, definite measures that could strengthen a safety barrier system.     

A conceptual Object-Oriented Bayesian Network (OOBN) for modeling aircraft carrier-based UAS safety risk

This paper illustrates the conceptual development of a demonstration Object-Oriented Bayesian Network (OOBN) to integrate the hazards associated with an experimental Unmanned Aircraft System (UAS) planned for deployment from an aircraft carrier. The final Air/Ship Integration (A/SI) demonstration model is characterized by a top-level Bayesian network model with nine sub-nets comprising 70 causal factors with 15 mitigations. With the creation of a probabilistic model, inferences about changes to the states of the causal factors given the presence or absence of controls or mitigations can be ascertained. These inferences build on qualitative reasoning and enable an analyst to identify the most prominent causal factor groupings leading to a prioritization of the most influential causal factors. Mitigation effects can be systematically studied and assessed. The A/SI OOBN demonstration model illustrates the construction of an integrative safety risk model that may be used to compute a higher-order system mishap probability for an experimental UAS that interacts with ship operations in a highly severe, dynamic sea environment. In addition to computing mishap probabilities, the Bayesian approach may also be used to support control contingency management for possible mitigation implementation.     

The diversity of high-frequency traders

The regulatory debate concerning high-frequency trading (HFT) emphasizes the importance of distinguishing different HFT strategies and their influence on market quality. Using data from NASDAQ-OMX Stockholm, we compare market-making HFTs to opportunistic HFTs. We find that market makers constitute the lion's share of HFT trading volume (63–72%) and limit order traffic (81–86%). Furthermore, market makers have higher order-to-trade ratios and lower latency than opportunistic HFTs. In a natural experiment based on tick size changes, we find that the activity of market-making HFTs mitigates intraday price volatility.     

On risk charges and shadow account options in pension funds

This paper studies the economic implications of regulatory systems which allow equityholders of pension companies to not only charge a specific premium to compensate them for their higher risk (compared to policyholders), but also to accumulate these risk charges in a so-called shadow account in years when they are not immediately payable due to e.g. poor investment results. When surpluses are subsequently reestablished, clearance of the shadow account balance takes priority over bonus/participation transfers to policyholders. We see such a regulatory accounting rule as a valuable option to equityholders and our paper develops a model in which the influence of risk charges and shadow account options on stakeholders’ value can be quantified and studied. Our numerical results show that the value of shadow account options can be significant and thus come at the risk of expropriating policyholder wealth. However, our analysis also shows that this risk can be remedied if proper attention is given to the specific contract design and to the fixing of fair contract parameters at the outset.     

On time-heterogeneous credibility estimation

Abstract

Let χ_i be the total claim amount of an insurance policy in calendar year i. We assume that the χ_i's are conditionally independent given an unknown random parameter ø, and that for all i. In the present paper it is under these assumptions shown how to calculate the credibility estimator of m(ø) by recursive updating. We also give estimators for the unknown parameters α_i, β_i, and ?_i based on portfolio data. Finally we mention some related models.     

Risk theory in a Markovian environment

Abstract

We consider risk processes _{t t?0} with the property that the rate β of the Poisson arrival process and the distribution of B of the claim sizes are not fixed in time but depend on the state of an underlying Markov jump process {Z_t } _t?0 such that β=β _i and B=B_i when Z_t=i . A variety of methods, including approximations, simulation and numerical methods, for assessing the values of the ruin probabilities are studied and in particular we look at the Cramér-Lundberg approximation and diffusion approximations with correction terms. The mathematical framework is Markov-modulated random walks in discrete and continuous time, and in particular Wiener-Hopf factorisation problems and conjugate distributions (Esscher transforms) are involved.     

Theme: Whole of government accounting— international trends

This article reconstructs the literature on corporate turnaround in terms of its recurring features. It then tests these against the experience of four very different cases of the turnaround or attempted turnaround of public and non-profit organizations. It concludes that while some concepts from the corporate literature usefully highlight important aspects, other critical complicating features of what is needed to achieve a turnaround in public and non-profit contexts would be overlooked or poorly treated if the situation were considered simply in these terms. These complicating features deserve the attention both of practitioners and researchers.     

The Implicit Costs of Motherhood over the Lifecycle: Cross-Cohort Evidence from Administrative Longitudinal Data

It is well known that the explicit costs of raising a child have grown over the past several decades. Less well understood are the implicit costs of having a child, and how they have changed over time. In this article, we are the first to examine the evolution of the implicit costs of motherhood over the lifecycle and across generations using high quality administrative data. We estimate that the lifetime labor market income gap between mothers and women who never have children (never-mothers) decreases from around $350,000 to $280,000 between women born in the late 1940s and late 1960s. Gaps tend to increase monotonically over the lifecycle, and decrease monotonically between cohorts. Our evidence suggests that changes in the gaps are caused by changing labor force participation rates.