These systems could collect, analyse and promulgate information about traffic levels, rates and speeds. This includes: historical, current, and forecast traffic. These systems could provide facilities for advance planning based on forecast traffic and immediate replanning based on actual traffic. For immediate replanning, at present, when we encounter congestion, there is very little information available on which to base decisions about changes to travel plans. In additional, for advance planning, improved facilities might have avoided encountering the congestion, and if widely used might have avoided the congestion from occurring altogether.