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 Spectra
Launched in 1991, the Optare Spectra is a double-decker bus body built on the DAF (now VDL) DB250 chassis.
The vehicle was developed as a joint project between Optare and DAF; it was based on the designs of the successful MCW Metrobus which had been jointly purchased by DAF and Optare, but they are by no means a restlyed Metrobus. With the launch of the DB250LF chassis sometime after production commenced, the Spectra was built to low-floor specification, and was one of the first low-floor double-decker buses available in the United Kingdom. The design is notable for the exclusion of a lower deck rear window, a practice that has become more commonplace. The bus typically seated 47 on the upper deck and 28 on the lower deck in single-door format.