There seems to be a dearth of peer reviewed, published research on the
subject. What little there is mainly concerns reflectors and solid
lighting, not blinking or flickering LED bicycle lamps. Nonetheless, it
may be possible to make some educated guesses from the following
references. My take is that it seems to be a safe guess that a red
bicycle "blinkie" light on the rear would not harm conspicuity and may
aid it, especially if a red or amber rear reflector is also used, but a
white blinkie on the front is insufficient to aid cyclist conspicuity in
any circumstance where being seen or avoiding a collision is most
needed. There is some newer research that concludes motorcyclists are
more conspicuous when motorcycles are equipped with pulsating headlamps,
but I have misplaced my references on the subject. However, most
flashing or blinking bicycle headlamps are nowhere nearly as bright as
motorcycle headlamps, nor do they provide the same side-to-side
conspicuity, so I would be skeptical about extending motorcycle
conclusions to cyclists.

Bear in mind, too, that laws often prohibit flashing lights. Most
current models of bicycle LED "blinkie" lights create a flickering
pattern, with at least one LED illuminated at all times; hence they
technically are not "flashing" lights.

I include De Valois, et al (6), below because I have seen it widely
cited, but I think Shoup (7), which appeared in the same publication,
says all you need to know about the former study.

1. Forester, J., "Bicycle Nighttime Safety Equipment Requirements of the
CPSC". March, 1996. Paper presented to Consumer Product Safety
Commission meeting. March, 1996. URL:
http://www.johnforester.com/Articles/Lights/cpsc9601.htm

2. Forester, John, Bicycle Transportation, The MIT Press, 1983.

3. Forester, John, “Nighttime Safety Equipment Requirements of the
Consumer Product Safety Commission”. URL:
http://www.johnforester.com/Articles/Lights/cpscreq.htm

4. Schubert, John, “Cycle Sense: Why Reflectors Don't Work. There are
optical reasons for all those crashes and deaths”. URL:
http://www.sheldonbrown.com/reflectors.html

5. De Valois, K., T. Takeuchi and M. Disch, "In the Dark: Seeing Bikes
at Night". Access No. 20; 14-19, Spring, 2002. University of California
Transportation Center Berkeley, CA 94720 –1782. URL:
http://www.brl.ntt.co.jp/people/takeuchi/access.pdf

6. Shoup, D., "Roughly Right or Precisely Wrong". Access No. 20; 20-25;
Spring, 2002. University of California Transportation Center Berkeley,
CA 94720 –1782. URL: http://www.uctc.net/access/access20.pdf.

7. Bernard S. Abrams, Arthur P. Ginsburg, Merrill J. Allen (Editor) and
Leslie Weintraub, Forensic Aspects of Vision and Highway Safety, Lawyers
& Judges Pub Co, 1996.

8. Brezina, E., and Kramer, M. An Investigation of Rider, Bicycle and
Environmental Variables in Urban Bicycle Collisions. Ontario Department
of Transportation, Technical Bulletin SE-70-01, October, 1970.

9. Kenneth Cross; Identifying Critical Behavior Leading to Collisions
Between Bicycles and Motor Vehicles; Office of Traffic Safety, State of
California; June, 1974.

10. Cross, Kenneth D. & Gary Fisher; A Study of Bicycle/Motor-Vehicle
Accidents: Identification of Problem Types and Countermeasure
Approaches; National Highway Traffic Safety Administration, Sept. 1977.

11. Forester, John, Bicycle Transportation, 2nd Edition. The MIT Press,
1994.

12. John S. Allen, “About Bicycle Reflectors”. March, 2003. URL:
http://www.bikexprt.com/bicycle/reflectors/index.htm

13. Forester, John, “Policy on Nighttime Protective Equipment of the
League of American Wheelmen”, American Wheelmen, League of American
Wheelmen, December, 1979. URL:
http://www.johnforester.com/Articles/Lights/lawnight.htm

14. Forester, John, “Nighttime Safety Equipment Requirements of the
Consumer Product Safety Commission”. URL:
http://www.johnforester.com/Articles/Lights/cpscreq.htm

15. Forester, J, "Bicycle Nighttime Protective Equipment: Literature
Presented to the Consumer Product Safety Commission". Summary of papers
presented at Consumer Product Safety Commission conference on bicycle
nighttime protective equipment, November, 1995. URL:
http://www.johnforester.com/Articles/Lights/cpscpap.htm

16. Lights surveys, Bicycle Victoria. URL:
http://www.bv.com.au/inform.php?a=7&b=259&c=2123

--

Darrell Noakes
Saskatoon, SK CANADA
www.BorealisOutdoor.com
www.SaskatoonCyclingClub.ca



Bob Sutterfield wrote:
> I wrote:
>> Can anyone point me to studies of safety comparing
>> blinking with solid bicycle lighting?
>
> I've seen citations of various US states' traffic laws, but here's the
> only
> allusion so far to commissioned research:
>
> http://tinyurl.com/uwghl is
> http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_611
>
> 218.hcsp
> which says
>> The use of flashing front and rear lamps on pedal cycles is becoming
>> commonplace, despite these not being permitted by the Regulations.
>> Research carried out by ICE Ergonomics Ltd concluded that flashing
>> lamps neither improve pedal cycle conspicuity nor impair it. Therefore
>> the Department has concluded that the current prohibition on flashing
>> lights on pedal cycles should be lifted so that cycle riders are free
>> to choose whether or not to fit flashing lamps.
>
> I haven't yet been able to find that research publication, but if
> that's an
> accurate summary of a credible study, I'll stop worrying about
> cyclists with
> only blinkies.
>

--

Darrell Noakes
Saskatoon, SK CANADA
www.BorealisOutdoor.com
www.SaskatoonCyclingClub.ca