Longer and heavier vehicles on the roads could result in large transport and economic benefits. In an on-going VTI project an economic estimate is made of the effects of allowing longer and heavier trucks in Sweden. A central part of that project is traffic safety analysis and risk assessment of longer and heavier vehicles. This review concerns potential traffic safety effects from the introduction of longer and heavier trucks than those currently allowed in Sweden. For this purpose, a summary of results from accident studies, literature summaries and in-depth studies of fatal accidents involving heavy trucks done in the past few years was made. In addition, a focus group study with truck drivers was conducted and results from a parallel VTI study concerning overtaking of longer trucks have also been included in order to give an overall picture of the possible traffic safety effects associated with the introduction of longer and heavier trucks in Sweden. Following are some of the recommendations, based on the aspects that have been addressed in this report: • Longer and heavier vehicles should mainly operate on main roads where it is possible to overtake heavy vehicles without fear of oncoming traffic. Longer and heavier vehicles should operate as little as possible in urban areas. • Longer and heavier vehicles shall be constructed for good stability, and be equipped with Electronic Brake System (EBS). • Longer and heavier vehicles puts greater demand on tires, brakes and especially maintenance and inspection. • Driver fatigue is a cause of an essential part of single-vehicle accidents with heavy vehicles. Drive and rest times may be harder to keep with the extra-long vehicles if rest areas, which are already today overcrowded along certain roads, are not extended. • The signs of the transition distance on 2+1 roads should be reviewed to possibly reduce the risk of dangerous situations and emergencies caused by overtaking of heavy vehicles. • Additional field studies on two-lane roads are necessary to determine whether there is a higher risk to overtake a 30 m long vehicle compared to overtaking a conventional heavy truck. (Author/publisher) This report may be accessed by Internet users at http://www.vti.se/en/publications/traffic-safety-effects-due-to-an-intr…
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