Editing Personal rapid transit (section)

====Control algorithms====
The typical control algorithm places vehicles in imaginary moving "slots" that go around the loops of track. Real vehicles are allocated a slot by track-side controllers. Traffic jams are prevented by placing north–south vehicles in even slots, and east/west vehicles in odd slots. At intersections, the traffic in these systems can interpenetrate without slowing.

On-board computers maintain their position by using a [[PID controller|negative feedback loop]] to stay near the center of the commanded slot. Early PRT vehicles measured their position by adding up the distance using [[odometer]]s, with periodic check points to compensate for cumulative errors.<ref name="FundOfPRT" /> Next-generation [[GPS]] and radio location could measure positions as well.

Another system, "pointer-following control", assigns a path and speed to a vehicle, after verifying that the path does not violate the safety margins of other vehicles. This permits system speeds and safety margins to be adjusted to design or operating conditions, and may use slightly less energy.<ref name="ControlPRT">{{cite web
 | url = https://www.telenor.com/wp-content/uploads/2012/05/T03_1.pdf
 | title = Control of Personal Rapid Transit Systems
 | pages = 108–116
 | publisher = Telektronikk
 | date = January 2003
 | access-date = August 30, 2017
}}</ref> The maker of the ULTra PRT system reports that testing of its control system shows lateral (side-to-side) accuracy of 1&nbsp;cm, and docking accuracy better than 2&nbsp;cm.