Mats Wiklund

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. Results: Driving speeds increased slightly on the wider road and on the road with a crash barrier, and the lateral driving position was nearer to the road center on the narrower road and on the road with a crash barrier. The HRV data did not indicate that participants experienced greater stress due to road width or due to the presence of a crash barrier. Participant experience captured in the oral questionnaires suggested that road width did not affect driver stress or driving patterns; however, the written questionnaire results supported the simulator data, indicating that a wider road led to increased speed. None of the participants felt that crash barriers made them feel calmer. Conclusions: We believe that there is a possibility that the increased speed on roads with crash barriers may be explained by drivers’ sense of increased security. This study demonstrates that an experimental design including experience-based data captured using both a simulator and questionnaires is productive. It also demonstrates that driving simulators can be used to study road features such as crash barriers. It seems more than likely that features such as street lamps, signs, and landscape objects could be tested in this way.

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. Results: About 20 percent of all those who receive the offer from the police accept contact with the social services or the care and treatment service, and approximately 40 percent of these also attend the consultation. There is a favorable fundamental attitude to the method among the participating authorities. However, some shortcomings in application are revealed. One example concerns drug drivers who are offered contact with the social services or the care and treatment service to a considerably lesser extent than drink drivers. Another neglected group are the people who are at first suspected of drink driving but are later found to have an alcohol concentration below the legal limit. Compared with those who have an alcohol concentration above the legal limit, this group is offered contact to a lesser extent and also have a lower propensity to accept the offer. Conclusions: The results indicate a strong support for the method from involved authorities, but participation could be improved by giving more attention to neglected groups.