Turn-by-turn navigation is a feature of some GPS navigation devices where directions for a selected route are continually presented to the user in the form of spoken and visual instructions. The system keeps the user up-to-date about the best route to the destination, and is often updated according to changing factors such as traffic and road conditions. Turn-by-turn systems typically use an electronic voice to inform the user whether to turn left or right, the street name, and how much distance to the turn. 
Devices and services
Major mapping services that offer turn-by-turn navigation, grouped by map data provider:
- Nokia Maps. Devices that use Navteq map data:
- Google Maps and Yahoo! Maps. Devices that use Tele Atlas map data:
- Android smartphones off-line using the free MapDroyd with maps from OpenStreetMap, Navteq or Tele Atlas
- Apple iPhone using iOS 6
- Apple iPhone < iOS 6 on-line or offline using various commercial software
- Waze, a free app providing turn-by-turn navigation on iOS, Android, Windows Mobile, Symbian, and BlackBerry OS
- Button, Kenneth J.; David A. Hensher (2001). Handbook of transport systems and traffic control. Emerald Group Publishing. p. 497. ISBN 978-0-08-043595-4 [Amazon-US | Amazon-UK].
- Targowski, Andrzej (1998). Global information infrastructure: the birth, vision, and architecture. IGI Global. p. 264. ISBN 978-1-878289-32-2 [Amazon-US | Amazon-UK].
- Jacko, Julie A. (2009). Human computer interaction. Springer Science+Business Media. p. 141. ISBN 978-3-642-02579-2 [Amazon-US | Amazon-UK].
- See comparison of web map services
- Brady Forrest (14 October 2009). "Google Shrinks Another Market With Free Turn-By-Turn Navigation". O'Reilly Media. Retrieved 4 November 2010.
- "MapDroyd". Retrieved 2011-03-16.
- "iPhone GPS apps". Navigadget. 29 June 2009. Retrieved 7 November 2010.