In article 2014092120183339822-nospam@nospamcom,
(eastender) wrote:

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).

Dayglo is brighter in daylight, impressively so when fresh. I suppose it may
not get much chance to be shown up, though.

--
Colin Rosenstiel