Navigational Rallying has been practiced in Canada since the early 1950’s and tests both driver and navigator. Instead of running flat-out, as in a performance rally, navigational events use the Time-Speed-Distance (TSD) formula.
In a TSD section, a particular average speed is listed and the teams must drive as close as possible to that speed. Checkpoints are placed at unknown locations in the TSD section and teams are penalized for passing them early or late. Average speeds are always within posted speed limits, and the road is not closed to the public, so teams must obey all traffic laws.
The route usually follows roads that are similar to those used in performance rallies: narrow winding forestry roads, ranch roads, and other less-traveled roads. Route finding is generally not difficult, but the navigator has a lot of work to do to keep the driver on time.