The steering law has been independently discovered and studied three times (Rashevsky, 1959; Drury, 1971; Accot and Zhai, 1997).
Its most recent discovery has been within the human–computer interaction community, which has resulted in the most general mathematical formulation of the law.
In this context, the steering law is a predictive model of human movement, concerning the speed and total time with which a user may steer a pointing device (such as a mouse or stylus) through a 2D tunnel presented on a screen (i.e. with a bird's eye view of the tunnel), where the user must travel from one end of the path to the other as quickly as possible, while staying within the confines of the path.
One potential practical application of this law is in modelling a user's performance in navigating a hierarchical cascading menu.
Many researchers in human–computer interaction, including Accot himself, find it surprising or even amazing that the steering law model predicts performance as well as it does, given the almost purely mathematical way in which it was derived.
The total time to navigative through all the goals, and thus through the tunnel, is Note that b is an experimentally fitted constant and let
We can let N grow arbitrarily large, making the length of successive straight tunnels become infinitesimal.
The total time to navigative through the curved tunnel is yielding the general form of the steering law.