In Saskatchewan the predominant type of accident on provincial highways is the single vehicle, off-the-road accident. In most cases the vehicle rolls. No doubt the lack of congestion on Saskatchewan highways is a contributing factor to the large proportion of single vehicle accidents. A pilot study has indicated that the standard accident reports do not give a complete picture of ditch encroachments. From 2.3 to 10.0 times the number of reported accidents are occurring. Cursory examination indicates that human error or inexperience is a major contributing factor. Since human behaviour or error is very difficult to change, the most positive step that highway engineers can take is the design and construction of safe and efficient ditches and traffic control devices. /author/
Abstract