On 2014-09-19 21:19:30 +0000, francis said:

Is there any reason that some London buses have white destination
blinds & some have yellow?


Answer by Boris Johnson:

White lettering on a black background is the maximum contrast
available, and TfL is using this format on bus destination blinds for
all new buses entering service, following improvements to powerful LED
lighting used to back-illuminate blinds.

TfL previously used ‘dayglo’ yellow on black at a time when they were
illuminated by ordinary bulbs or florescent tubes. Since then, TfL has
reduced the number of words displayed and introduced much larger
numbers and very bold destinations to increase visibility.

There are some other advantages of black and white over dayglo yellow
which are not immediately apparent. Dayglo yellow fades over time. The
route numbers fade more quickly as they are changed less often than
destination. Thus we have inconsistency on vehicles.

The white on black that will now be used as the standard for new
vehicles fully complies with the Discrimination Disability Act, as well
as meets legibility standards. In addition, the heritage Routemasters
on routes 9 and 15 have always retained their black and white blinds,
and the prototype New Bus for London vehicles on route 38 were
introduced with them. Throughout this time, no concerns from passengers
have been raised regarding their use.

http://mqt.london.gov.uk/mqt/public/...on.do?id=47730


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I'd add that there may be a colour blindness issue as well, although
yellow is not usually a problem for men who are colour blind (red/green
wavelengths are the usual problem and one reason I could never be an
airline pilot or train driver).

E.