Double-decker bus
The first commercial horse-drawn double-decker omnibuses were introduced in England in 1847 by Adams & Co. of Fairfield, Bow, then improved upon by John Greenwood, who introduced a new double-decker in 1852.
Bilevel rail car
In Japan, double-decker trains are used either to show better scenery, or to increase seat capacity. In Tokyo area commuter trains, double-decker cars are generally used as "Green Cars", a type of reserved-seating-only cars with better accommodations than the regular commuter cars.
The first Japanese double-decker train appeared in 1904. It was Type 5 train of Osaka City Tram. Sightseeing trains that feature double-decker carriages include the JR Shikoku 5000 series, Keihan 8000 series, JR Central 371 series, and Odakyu 20000 series RSE. The first JNR/JR double-decker trains were 200 series Shinkansen and 100 series Shinkansen, for Shinkansen lines.