Effects of human trampling on abundance and diversity of vascular plants, bryophytes and lichens in alpine heath vegetation, Northern Sweden.

This study investigated the effects of human trampling on cover, diversity and species richness in an alpine heath ecosystem in northern Sweden. We tested the hypothesis that proximity to trails decreases plant cover, diversity and species richness of the canopy and the understory. We found a significant decrease in plant cover with proximity to the trail for the understory, but not for the canopy level, and significant decreases in the abundance of deciduous shrubs in the canopy layer and lichens in the understory.

The effect of different delineator post configurations on driver speed in night-time traffic: a driving simulator study.

The aim of the study was to investigate how different delineator post configurations affect driver speed in night-time traffic. In addition, the potential speed effect of introducing a secondary task was investigated. The study was carried out in a car simulator on a road stretch including straight road sections as well as curves with different radii.

Stakeholders' opinions on a future in-vehicle alcohol detection system for prevention of drunk driving.

Introduction: There is a common understanding that driving under the influence of alcohol is associated with higher risk of being involved in crashes with injuries and possible fatalities as the outcome. Various countermeasures have therefore from time to time been taken by the authorities to prevent drunk driving. One of them has been the alcohol interlock.

Dominance hierarchies, diversity and species richness of vascular plants in an alpine meadow: contrasting short and medium term responses to simulated global change.

We studied the impact of simulated global change on a high alpine meadow plant community. Specifically, we examined whether short-term (5 years) responses are good predictors for medium-term (7 years) changes in the system by applying a factorial warming and nutrient manipulation to 20 plots in Latnjajaure, subarctic Sweden. Seven years of experimental warming and nutrient enhancement caused dramatic shifts in dominance hierarchies in response to the nutrient and the combined warming and nutrient enhancement treatments.

Urban air quality: the challenge of traffic non-exhaust emissions.

About 400,000 premature adult deaths attributable to air pollution occur each year in the European Region. Road transport emissions account for a significant share of this burden. While important technological improvements have been made for reducing particulate matter (PM) emissions from motor exhausts, no actions are currently in place to reduce the non-exhaust part of emissions such as those from brake wear, road wear, tyre wear and road dust resuspension.

Safe mobility for elderly drivers--considerations based on expert and self-assessment.

To further understand the needs of the growing population of elderly drivers and create solutions for safe mobility it is important to understand the driving scenarios and aspects in day to day traffic that may be of challenge for this group. More so, individual differences in how drivers perceive their own driving ability may have an effect on how individuals limit their mobility and/or increase their exposure to risk situations, with a potential negative effect on safety. In this study two sets of assessments have been used in order to identify scenarios and aspects needing consideration in creating safe mobility for elderly drivers; an expert assessment using on-road driving together with assessments through semi structured in-depth interviews.

Evaluation of new speed limits in Sweden: a sample survey.

Objective: The study sought to estimate changes in actual driving speed occurring after new speed limits were introduced in Sweden's rural road network.

Method: The effects of speed limit changes were estimated for 7 groups of roads of different types and initial speed limits. To study the effects on the entire road network and not only at specific road sites, a sampling survey was conducted in which speed was measured at randomly selected sites before and after the speed limit changes.

An international review of the frequency of single-bicycle crashes (SBCs) and their relation to bicycle modal share.

Objectives: To study cyclists' share of transport modes (modal share) and single-bicycle crashes (SBCs) in different countries in order to investigate if the proportion of cyclist injuries resulting from SBCs is affected by variation in modal share.

Methods: A literature search identified figures (largely from western countries) on SBC casualties who are fatally injured, hospitalised or treated at an emergency department. Correlation and regression analyses were used to investigate how bicycle modal share is related to SBCs.

Crash barriers and driver behavior: a simulator study.

Objective: The study examines how drivers experience a conventional W-beam guardrail (metal crash barrier) along both sides of narrow versus wider roads (single carriageway with 2 lanes) in terms of stress, feelings, and driving patterns and whether subjective experience concurs with the actual driving patterns captured by the quantitative data.

Methods: The study used different methods to capture data, including the VTI Driving Simulator III (speed and lateral vehicle position) in conjunction with electrocardiogram (ECG) data on heart rate variability (HRV) and questionnaires (oral during driving and written after driving). Eighteen participants--8 men and 10 women--were recruited for the simulator study and the simulator road section was 10 km long.

Effects of electronic billboards on driver distraction.

Objective: There is an increase in electronic advertising billboards along major roads, which may cause driver distraction due to the highly conspicuous design of the electronic billboards. Yet limited research on the impact of electronic billboards on driving performance and driver behavior is available. The Swedish Transport Administration recently approved the installation of 12 electronic billboards for a trial period along a 3-lane motorway with heavy traffic running through central Stockholm, Sweden.

Weak central coherence in patients with Alzheimer's disease(•).

Central coherence refers to the ability to interpret details of information into a whole. To date, the concept of central coherence is mainly used in research of autism, Asperger's syndrome and recently in the research on eating disorders. The main purpose of the present study was to examine central coherence in patients with Alzheimer's disease.

Truck drivers' opinion on road safety in Tanzania--a questionnaire study.

Objective: Even though the traffic fatality risk (fatalities per 100,000 inhabitants) in Tanzania is quite low, the fatality rate (fatalities per 10,000 vehicles) is one of the highest in the world. With increasing vehicle density this means that the number of people dying in traffic will increase dramatically in the near future. Therefore, it is important to implement measures to increase traffic safety as soon as possible, and in order to be able to do this in an efficient way, it is important to investigate where the main problems lie.

Development of a method for detecting jerks in safety critical events.

A new method for detecting jerks in safety critical events, based on the characteristics of the braking caused by the driver in time critical situations, has been developed and evaluated in a small pilot test and also applied on a naturalistic driving study. A portable event data recorder, capable of measuring and recording acceleration profiles for a predetermined time period before and after the safety critical situation, has also been developed to ensure high data quality used to evaluate the proposed method. Thus, an analysis of the acceleration profile is possible during the entire braking event.

Traffic emission factors of ultrafine particles: effects from ambient air.

Ultrafine particles have a significant detrimental effect on both human health and climate. In order to abate this problem, it is necessary to identify the sources of ultrafine particles. A parameterisation method is presented for estimating the levels of traffic-emitted ultrafine particles in terms of variables describing the ambient conditions.

Estimation of the severity of safety critical events.

Today, various measures are used to estimate the severity of a traffic conflict. However, these measures are all limited to estimating the crash risk and do not include any estimates of the possible consequences of a potential crash. In accident analysis the estimated severity of the event is related to the outcome of the crash, such as injury levels.

Measuring driver impairments: sleepiness, distraction, and workload.

Snow was falling heavily when Sarah was driving on a slippery road to her cousin's country cottage. It was dark outside, and the visibility was poor. She had planned to arrive before sunset, but the rental service had made a mistake, and it took hours before she got her rental car at the airport.

A longitudinal study of semantic memory impairment in patients with Alzheimer's disease.

Introduction: The present study explored the nature of the semantic deterioration normally displayed in the course of Alzheimer's disease (AD). The aim was to disentangle the extent to which semantic memory problems in patients with AD are best characterized as loss of semantic knowledge rather than difficulties in accessing semantic knowledge.

Method: A longitudinal approach was applied.

The impact of tunnel design and lighting on the performance of attentive and visually distracted drivers.

The crash risk in tunnels is lower than on the open road network, but the consequences of a crash are often severe. Proper tunnel design is one measure to reduce the likelihood of crashes, and the objective of this work is to investigate how driving performance is influenced by design factors, and whether there is an interaction with secondary task load. Twenty-eight drivers participated in the simulator study.

Jerky driving--An indicator of accident proneness?

This study uses continuously logged driving data from 166 private cars to derive the level of jerks caused by the drivers during everyday driving. The number of critical jerks found in the data is analysed and compared with the self-reported accident involvement of the drivers. The results show that the expected number of accidents for a driver increases with the number of critical jerks caused by the driver.

Cooperation between police and social treatment services offering treatment to drink and drug drivers--experience in Sweden.

Objective: To describe and analyze a measure that has been introduced in Sweden with the objective of quickly offering treatment for the alcohol or drug problems suspected drink or drug drivers may have. The goal of the measure is that every suspected drink or drug driver shall, as soon as apprehended by the police, be offered contact with the social services or the dependency care and treatment service, which can offer a consultation and, if needed, suitable treatment.

Method: Interviews and questionnaire surveys, as well as forms that describe the treatment received by each individual case.

Predicting visual distraction using driving performance data.

Behavioral variables are often used as performance indicators (PIs) of visual or internal distraction induced by secondary tasks. The objective of this study is to investigate whether visual distraction can be predicted by driving performance PIs in a naturalistic setting. Visual distraction is here defined by a gaze based real-time distraction detection algorithm called AttenD.

Are driving and overtaking on right curves more dangerous than on left curves?

It is well known that crashes on horizontal curves are a cause for concern in all countries due to the frequency and severity of crashes at curves compared to road tangents. A recent study of crashes in western Sweden reported a higher rate of crashes in right curves than left curves. To further understand this result, this paper reports the results of novel analyses of the responses of vehicles and drivers during negotiating and overtaking maneuvers on curves for right hand traffic.

Handling of buses on slippery roads during the influence of side wind--a study of the effects of different tyres.

Accident statistics assembled by the Swedish National Road and Transport Research Institute (VTI) have shown that buses are overrepresented when it comes to accidents on icy and snowy roads. For a better understanding of the problem, the performance of modern summer and winter tyres on winter road conditions had to be assessed. The objective of this work has been to go beyond standard road grip studies, and instead investigate how the driver's possibility to deal with one challenging situation depends on the tyres and tyre configuration.

Sleepiness and prediction of driver impairment in simulator studies using a Cox proportional hazard approach.

Cox proportional hazard models were used to study relationships between the event that a driver is leaving the lane caused by sleepiness and different indicators of sleepiness. In order to elucidate different indicators' performance, five different models developed by Cox proportional hazard on a data set from a simulator study were used. The models consisted of physiological indicators and indicators from driving data both as stand alone and in combination.