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.
Optare MetroDecker
The Optare MetroDecker is an integral twin-axle double-decker bus manufactured by Optare. Unveiled in May 2014, four examples were built as demonstrators.