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.
History of bus transport in Hong Kong
Following the end of restriction of buying new buses from countries of Commonwealth of Nations, KMB introduced one German-built Mercedes-Benz O305 double-decker in 1983. It was followed by another 40 in 1985.