Destination sign

[3] For many decades, the most common type of multiple-option destination sign was the rollsign (or bus blind, curtain sign, destination blind, or tram scroll): a roll of flexible material with pre-printed route number/letter and destinations (or route name), which is turned by the vehicle operator at the end of the route when reversing direction, either by a hand crank or by holding a switch if the sign mechanism is motorized.

The upper and lower rollers are positioned sufficiently far apart to permit a complete "reading" (a destination or route name) to be displayed, and a strip light is located behind the blind to illuminate it at night.

A small viewing window in the back of the signbox (the compartment housing the sign mechanism) permits the driver to see an indication of what is being shown on the exterior.

Although these sign systems are normally accurate, over time the blind becomes dirty and the computer may not be able to read the markings well, leading occasionally to incorrect displays.

Most Transport for London buses use a standard system with up & down buttons to change the destination shown on the blinds & a manual override using a crank.

In Hong Kong, plastic signs had been used since the mid-1990s on Kowloon Motor Bus (KMB) and Long Win Bus (LWB) buses to replace rollsigns on the existing fleet, and became a standard equipment until 2000 when electronic display became mainstream, with the exception of single decker buses, presumably because the number of destinations in the network was so large that rolling the destination between every trip was impractical.

[citation needed] In the United States, the first electronic destination signs for buses were developed by Luminator in the mid-1970s[1] and became available to transit operators in the late 1970s, but did not become common until the 1980s.

An internal sign, that could also provide different kinds of information such as the current stop and the next one, aside from the route number and destination, may also be installed.

An example of LED-type destination signs on an AC Transit bus. On the front sign, the bottom line of text changes every few seconds to list multiple destinations along the route.
A rollsign-equipped trolleybus in Arnhem , Netherlands
A rollsign on the MBTA Red Line in Boston . This sign has a hand crank to change the destinations displayed, but many rollsigns are motorized.
A motorized rollsign changing in a San Francisco Muni train
Two types of light rail car on the MAX system in Portland, Oregon , both fitted with rollsigns, in 2009. This photo illustrates how rolls/blinds allow use of color and of symbols, such as the airplane icon shown here.
A typical KMB bus, manufactured in the 90s, using plastic signs as destination signs, with separate plates for the destination and the route number
A flip-disc display on a TriMet bus
KMB buses with Hanover-brand flip disc destination signs in Hong Kong [ a ]
Full-color LED destination sign on a train in Japan