.mw-parser-output .hidden-begin{box-sizing:border-box;width:100%;padding:5px;border:none;font-size:95%}.mw-parser-output .hidden-title{font-weight:bold;line-height:1.6;text-align:left}.mw-parser-output .hidden-content{text-align:left}@media all and (max-width:500px){.mw-parser-output .hidden-begin{width:auto!important;clear:none!important;float:none!important))You can help expand this article with text translated from the corresponding article in German. (January 2016) Click [show] for important translation instructions. View a machine-translated version of the German article. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Consider adding a topic to this template: there are already 9,088 articles in the main category, and specifying|topic= will aid in categorization. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing German Wikipedia article at [[:de:Zweirichtungsfahrzeug]]; see its history for attribution. You should also add the template ((Translated|de|Zweirichtungsfahrzeug)) to the talk page. For more guidance, see Wikipedia:Translation.

You can help expand this article with text translated from the corresponding article in Dutch. (January 2016) Click [show] for important translation instructions. View a machine-translated version of the Dutch article. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Consider adding a topic to this template: there are already 378 articles in the main category, and specifying|topic= will aid in categorization. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Dutch Wikipedia article at [[:nl:Tweerichtingsvoertuig]]; see its history for attribution. You should also add the template ((Translated|nl|Tweerichtingsvoertuig)) to the talk page. For more guidance, see Wikipedia:Translation.

A bi-directional vehicle is a vehicle that can be driven in either direction, forwards or backwards. Usually, the term refers to rail vehicles, such as trains or trams, and some airside transfer buses, that are equipped with driver's cabs at both ends. These vehicles generally have entry and exit doors on either side of the vehicle.

One major benefit of bi-directional vehicles is the ability to reverse direction at a terminal station with a stub-end track. On a system using double track, a crossover switch is often used to move the vehicle to the other track. This situation contrasts with the use of uni-directional vehicles, which requires the use of a balloon loop, triangle junction, or turntable to reverse direction.

Aside from eliminating the need for complicated railway infrastructure to turn vehicles around, the presence of doors on either side of the vehicle enable the use of island platforms. These extra doors come at the cost of reduction of seating on board the vehicle.