nwmtnbkr

xtrajack,

I am confident that you could wire your own brake light, however, since the Nashbar unit is on sale right now, price-wise you can't do much better. Using a micro lever switch, you have three connector terminals--C, NC, and NO, which allows them to be wired in Normally Open or Normally Closed position. Connect your hot wires to the angled C terminal, then connect the load wires to NO terminal, since you want the light to go on when the brake is pressed and the lever switch's rod is pushed in. I've used red as the "hot" wire and black as the load wire in this illustration. I've used the two holes in the body of the switch to run small zip ties to connect the switch to the brake cable.

Giro

Unfortunately, "Motorist Overtaking" type collisions as defined in the bicycle crash literature and the most commonly used crash documenting software, PBCAT (Pedestrian and Bicycle Crash Analysis Tool), are much more frequent than that and result in a disproportionate portion of fatalities.

Some specifics copied from a thread on another bicycle forum:

The often cited major US study is Bicycle and Pedestrian Crash Types of the Early 1990's (FHWA-RD-95-163, a 1
. Of their 85 crash types, 5 (6 including "Type unknown) are in the "Class D: Motorist overtaking bicyclist". They compared their data to the 1977 Cross and Fisher study and for this class of crashes:

1977 study, Total Fatal=166 of which 37.8% were motorist overtaking, Total Nonfatal=753 of which 10.5% were overtaking
1990's study, Total Fatal=41 of which 29.3% were motorist overtaking, Total Nonfatal=2453 of which 9.8% were overtaking.

As you can see, the Motorist Overtaking class has a disproportionate fraction of the fatalities in both studies and and was not a rare crash.

However, all of that data is (obviously) before cell phones, texting, and a variety of other new causes of distracted driving as well as possible improvements in highway safety such as better motor vehicle headlights, better bicycle reflectors, better bicycle lights etc. and improvements in emergency trauma care. Some more recent data:

Wisconsin 2003
City crashes: 5.22% motorist overtaking;
but for Rural crashes 12.02%; Motorist Overtaking Undetected Bicyclist was the most common crash type.

City of Toronto Bicycle/Motor-Vehicle Collision Study, 2003 (city, not rural) found motorist overtaking was 11.9% of collisions, the second most common type, accounting for 4 of the 10 fatalities:

N. Carolina crashes from 2001 through 2007 rural/urban vs. crash type and aggregating the motorist overtaking collisions you get:
Urban, motorist overtaking: 373 of 4550 = 8.198% of all crashes
Rural, motorist overtaking: 553 of 2194 = 25.205% of all crashes

Further details on the N. Carolina data including graphs showing a steady increase in the percent due to motorist overtaking to about 30% of rural crashes in 2007 in this thread.

However, using that statistic for getting hit due to bicycle braking is a gross misuse of the data because in the large majority of the cases (see edit below) the bicyclist was not stopping and getting run over!

I think one of the reasons brake lights on bicycles may not be as important as on cars is because under good braking conditions (dry pavement etc.) four wheel motor vehicles can stop much faster than an upright diamond frame bike. Wilson's Bicycling Science 3rd edition goes through the physics. If your bike's brakes are good, you go over the handlebars at about 0.5g deceleration. Motor vehicles on dry pavement can brake to the limit of adhesion of the tires on the pavement, about 0.8 g deceleration. That means they can stop in 40% less distance than you can (0.8 / 0.5 = 1.6, so 0.4 less = 40%). Wilson adds this is why cyclists should never follow closely behind motor vehicles; they can stop a lot faster than you can. The exception (in principle) are tandems and recumbents. If their brakes are good enough, they too can brake to the adhesion limit (but with only two wheels and no anti-lock, maybe not quite as fast). Still, I wouldn't draft a tandem or recumbent without both of us being aware of the potential differences in braking ability.

The brake lights may very well help (more in an urban environment?), but probably a rear view mirror, some looks back over the shoulder, being highly visible from the rear, etc. are more likely to reduce your chance of being run over in general, not just while braking you bike.

Edit: Since depending on how a PBCAT database is set up, it may be ambiguous in the "Overtaking" categories cross tabulated with the "Fault" field if braking was involved. I went back to the Bicycle and Pedestrian Crash Types of the Early 1990's and on page 86 the table for Crash Characteristics lists under Bicycle Maneuver "Slowing Stopping 1.2%, Stopped 0.9%". Thus at most, with 10.8% of crashes in the Motorist Overtaking types, only (1.2% + 0.9%) / 10.8% = 22.7% were associated with bicyclist slowing or stopping. Old data, but I suspect it may not have increased that much and thus is at most a minor part of the "Motorist Overtaking" types.

nwmtnbkr

Since signal lights aren't required on bicycles, there's no real data on their affect, or lack thereof, in cycling safety. However, there is a significant amount of data on motorcycle accidents, starting with the Hurt Report issued in the 1980s, and most conclude that motorists often don't detect smaller vehicles and that determining the speed of smaller vehicles is difficult. Recent governmental and industry reports (including GM's) find that daytime running lights and and bright turn signals are effective in getting motorists to see motorcycles and understand the intentions of the operator. Bright LEDs seem to be promising when used for signal lighting.

I think it's important for cyclists to have turn signals. Brake lights don't hurt either. Since I was installing turn signals on my bike I added a brake light at the same time. I know I've said it once already, but signal lights and a brake light do seem to have a positive affect on motorists' reaction to me--they give me more berth when I start signaling a turn before reaching an intersection and when I'm stopped at a stop sign or stop light. I'm glad I put the signal lights on my bike and I will add them to the folder I'm planning on purchasing.

intheways

I'm curious as to whether anyone would know if it's possible to wire something like these: https://www.ravx.com/2010_product_pag...led_plugs.html to a switch for turn signals?

nwmtnbkr

It's a little hard to say with certainty, not seeing the innards of these self-contained lights. However, where there's a will there's a way. If you're patient and good with a soldering iron, you may be able to de-solder the wiring to the internal battery holder, remove that holder and then solder the wire to longer leads to a toggle switch, which will be connected to a separate battery (you shouldn't need a lot of battery power).

It would be cheaper to go with something like this--a flashing led wired to a battery case with switch. https://cgi.ebay.com/RED-FLASHING-5mm...in_0?hash=item
Better yet, if you want only one battery source and one center off toggle, buy one or more of these flashing leds.
https://cgi.ebay.com/FLASHING-LED-5mm...item335385d54b

ItsJustMe

I really thing that for turn signals to be effective on a bike, they need to clearly be turn signals. People are used to blinking lights on bikes, and they don't expect them to be turn signals; who's ever seen a turn signal on a bicycle?

I really think you need an integrated full set of lights, so that, for instance, when left is indicated, the right light is on steady and the left is blinking at a normal rate for a turn signal (about 1.5 hz, maybe a little faster). If you just have one light blinking, then it's going to be perceived as a blinkie, not as a turn signal.

I'd be nervous about this anyway; if you use turn signals, will you stop using hand signals? It's such an odd thing to see on a bike, no matter how it's set up I'm afraid a lot of people won't realize what it is. Lots of people don't know what hand signals are either, but at least around here they at least think "that guy's doing something weird, I'm going to keep an eye on him."

xtrajack

I think these would fit the bill. As nwmtnbkr stated, (thank you for the link and the info.). they are/ could be considered pricey.

BTW, Guess what I am getting for my birthday?

intheways

Thanks for the info and I appreciate the comments. I agree that the unit should probably be integrated and be somewhat like MC turn signals.

Time to do some more thinking.

nwmtnbkr

xtrajack,

That's great. After you get them and have a chance to use them, let us know what you think about the Winkkus. Please post some photos when you have a chance, too.