I am not even sure about the legality of this in the UK.
Our rules state the following
Statutory Instrument 1989 No 1796 The Road Vehicles Lighting Regulations 1989 said:
Lamps to show a
steady light
13.—(1) Save as provided in paragraph (2),
no vehicle shall be fitted with a lamp which automatically emits a flashing light.(2) Paragraph (1) does not apply in respect of-
(a) a direction indicator;
(b) a headlamp fitted to an emergency vehicle;
(c) a warning beacon or special warning lamp;
(d) a lamp or illuminated sign fitted to a vehicle used for police purposes;
(e)
a green warning lamp used as an anti-lock brake indicator; or(f) lamps forming part of a traffic sign.
The regulations were amended in 2005 to permit the use of flashing position lights for pedal cycles and attachments thereto.
Statutory Instrument 2005 No 2559 The Road Vehicles Lighting Amendment Regulations 2005 said:
Amendments to regulation 13 (lamps to show a steady light)
6. In regulation 13(2)—
(a) the word "or" immediately following sub-paragraph (e) shall be omitted;
(b) after sub-paragraph (f) there shall be added—
" (g) a front position lamp capable of emitting a flashing light (whether or not it is also capable of emitting a steady light) which is fitted to—
(i) a pedal cycle; or
(ii) a trailer drawn by, or a sidecar attached to, a pedal cycle;
and which, if it is a lamp which is required to be fitted pursuant to regulation 18, is capable, when emitting a flashing light, of emitting light to the front of the pedal cycle, trailer or sidecar (as the case may be) of an intensity of not less than 4 candelas; or
(h) a rear position lamp capable of emitting a flashing light (whether or not it is also capable of emitting a steady light) which is fitted to—
(i) a pedal cycle; or
(ii) a trailer drawn by, or a sidecar attached to, a pedal cycle;
and which, if it is a lamp which is required to be fitted pursuant to regulation 18, is capable, when emitting a flashing light, of emitting light to the rear of the pedal cycle, trailer or sidecar (as the case may be) of an intensity of not less than 4 candelas."
The only time from my interpretation of that law which would be "allowable" is under the industry standard of alerting following drivers of heavy (ABS assisted) braking, which under our laws state that the warning light should be green (I guess the industry is ignoring that
)
