Abstract
Free speeds are defined as the speeds at which vehicles are driven when the drivers are not influenced by other vehicles. In general only some of the drivers in a traffic stream will be able to drive at their free speed. A method has developed to estimate the distribution of free speeds from the speeds of free and non- free vehicles on a cross- section.The method has been evaluated by using two simple simulation models and is applied to data from high flow two- lane rural roads. It was found that a large part of the free speeds are higher than the speed limit. Free speeds in rush hours tend to be somewhat higher than speeds during the rest of the day.