Dear Arthur Ross,

That was excellent information.  It is obvious that the Cat Eye Opti-Cube is not suitable for bicycles.  It is an excellent flashlight for around the house, though.  One cannot adequately see more than ten feet on the roadway and I ride at twenty miles per hour.  Fortunately, I know my roadway and use the same one for training.   Possibly they don't even make a bike light which could put out a beam as you describe.  And if it is set for that distance, the imprecision of such lights if strapped on would certainly blind oncoming bicyclists.  Is there any solution?  And if the ten foot focused light costs $4O, just think of what the sixty foot focused light must cost?

Eric

Ross, Arthur wrote:
Let's take a best case scenario.  An experienced bicyclist able to
achieve 0.5 G deceleration, riding on a good, hard, dry surface,
traveling at 15 miles per hour. Braking distance for 15 mph at 0.5G is
15.1 feet.  In terms of reaction time, tables from the 1980's used .75
seconds.  Tables I have seen more recently use 1 to 2 seconds.  In 1
second at 15 mph you travel 22 feet.  Thus at 15 miles per hour with a 1
second reaction time you need a light that lets you see at least about
40 feet ahead of you.  If you can only see 20 feet ahead of you, you
should slow down to 10 miles per hour to be safe.  If you are traveling
20 mph get the best light available (56 feet braking plus 1 sec reaction
time).

Arthur



Arthur Ross, Pedestrian-Bicycle Coordinator
City of Madison Traffic Engineering Division
215 Martin Luther King, Jr. Blvd., Suite 100
PO Box 2986
Madison, WI  53701-2986
608/266-6225


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of John Martin
Sent: Thursday, December 11, 2008 12:19 PM
To: Eric Westhagen
Cc: Meiers, Steve; BikiesSubmissions
Subject: Re: [Bikies] Finding opportunity from crisis? (Bikie attack)

Topic: bike lights

I agree with Eric about the cost of "cheap" bike lights. They used to be
a pain because the batteries would drain quickly, but with LEDs, even
the cheap ones seem to be getting expensive.

My question is whether bikes actually need to be "focused" and "white."
In my experience, the "cheap" LED lights offer next to nothing in terms
of helping me see where I'm going. If anything, they're distracting.
What I want from them is that cars see me from the front, so I'd rather
have a bright unfocused light that flashes in all directions (except at
my eyes). 

So, are there cheap *unfocused* front lights? Any recommendations?

On Dec 11, 2008, at 12:05 PM, Eric Westhagen wrote:

  
We have discussed bike lights from all sides in previous years.  And 
nobody should venture out at dusk or later without a red light for 
their own protection.  But the lack of a focused white light seems 
more of a question as far as bike to bike accidents are concerned,
and these white lights seem  not as cheap as has been implied here.   
Maybe there are cheap white lights, but I have not seen them myself.  
I do know that my model of light, the Cateye Opti-cube is a $30-$40 
light, depending on where one buys it.  Are there actually cheap 
focused lights for sale at Madison bike shops?  My Cateye, cost $30 
something at a Seattle bike shop and it was in the $40 range listed 
"on line."  Before one promotes white lights at a give away status, 
some cheaper source of reliable, well focused lights must be found.  
Does anybody have a suggestion?

Eric Westhagen
    

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