Tuesday, July 28, 2009

Coming Back At You

Or, "Reflections On Being Seen At Night"


Texas requires:

"SAFETY EQUIPMENT. sec. 551.104 ...(b) A person may not operate a bicycle at nighttime unless the bicycle is equipped with:

(1) a lamp on the front of the bicycle that emits a white light visible from a distance of at least 500 feet in front of the bicycle; and
(2) on the rear of the bicycle:
(A) a red reflector that is:
(i) of a type approved by the department; and
(ii) visible when directly in front of lawful upper beams of motor vehicle headlamps from all distances from 50 to 300 feet to the rear of the bicycle; or
(B) a lamp that emits a red light visible from a distance of 500 feet to the rear of the bicycle."

So where do I go to find out what reflectors are "approved by the department"?

So do either of my bicycles comply with the law? My single-speed above or my main ride below?


If my front light is operating, and my Planet Bike Super Flash (PBSF) tail-light is not, then only my single-speed would be legal, as I have no red reflectors on the back of my main bike, though I do have a red patch of reflective tape on my helmet. This is assuming that my reflective tape would meet the approval of "the department".

Legalities aside, is the minimum lawful requirements adequate? What can be done to maximize nighttime visibility? What is reasonable? What are the compromises I have made and why?

For all practical purposes, reflectors are helpful to be seen by overtaking and oncoming traffic only, and leave you invisible to cross traffic vehicles. Reflectors, by their nature, "send back" to the source a portion of the light that falls on it. Different reflectors and reflective tape are better at this than others. There are a lot of sites dedicated to the question of which one is better, and for what purpose, with side by side pictures and stats and on, and on, and on... It is a guy thing. I am going to cut through all that static for you and talk about the stuff that works with cycling, so you don't have to plow through considerations for aviation, railroads, marine use, trucking, chemical exposure and on, and on, and on...

Rigid plastic reflectors, of the type that came on the bike when it was sold to you, in general do a better job of returning light to it's source than tapes. (Absolute brightness) But absolute brightness is just a part of the equation. There is also perceived brightness.

A reflective surface will always be have a greater perceived brightness the greater it's area. Thus a reflector of a greater absolute brightness can seem to be "dimmer" than an inferior reflector if the inferior's reflective surface area is a lot bigger.

This leads me to the conclusion that the minimum legal requirements of a red reflector to the rear is inadequate for the task of being seen at night. A positive light source is necessary to be seen from the side or from an angle. You can trust me on this: reflectors only work when headlamps fall on them, and it is a surprisingly narrow angle of observability. The more frequent hazard to a cyclist is from crossing traffic, and a cyclist's reflectors are invisible to them. For a brief, but clear explanation, see John Schubert's essay on it. To find source data and a rant about it, this is the best!

I have discarded the notion of using rigid reflectors, as they are small and I dislike hanging hardware on my bicycle. The best reflective tape for our purposes is DOT/NHTSA 49CFR571.108 and SOLAS (Save Our Lives At Sea) rated tapes. SOLAS tape reflects about the same as DOT tape, and tends to be more durable, but DOT tape is easier to find. Both are spendy.

So you can see that I have gone for "area" in applying reflective tape!





When it comes to lights, there are basically three categories. Lights to "see by", lights to "be seen by" and inadequate. Lights to "see by" are so costly I have chosen to get lights to "be seen" instead. And since that is my goal, to stand out on the road, I run my positive light sources on "blink" mode. My tail light, as mentioned before is a PBSF, and my headlights are Cateye HL-EL135. While looking for the model number, I noticed their Uno which according to them is a bit brighter and lighter. (Whoo hoo! But it will require more frequent battery changes.) They will likely replace my present ones when they need to be replaced.

On my multi-speed bicycle, I have slung the light underneath the handlebars for aesthetic reasons, but it is not designed to operate that way. To prevent the battery cover from coming off (I ride on fairly rough roads) and another mount failure, I have employed a rather inelegant "electrical tape solution".



Because I am car-free, I can expect to travel after dark. So I want to have lights on my bikes at all times, and I carry spare batteries. I don't run them in the daytime beause, after all, I ride in the left third of the lane!

I am careful at night to ride on familiar roads, avoiding roads with known hazards. This is an operational compromise for not running with lights to "see by". My single-speed is expected to be pressed into service on foul weather trips, and it has more area for tape to be mounted because of its fenders. I also put both spoke reflectors on the front wheel. As Steve pointed out, not likely to be of much help, what can I say? (ChipSeal shrugs)

However, I will dispute his contention that I have put reflective tape "on the sides" of my bike. Reflective tape has the ability to reflect back to its source even when struck from a very high angle. Here are two pictures, taken with low sun, at an approximate angle displayed to overtaking and opposing traffic.



Oh, and one last thing, sometimes tape has uses beyond reflective duties! I ride on gravel roads with some frequency, and carbon fiber is allergic to dings. I have put reflective tape on the underside of my down-tube to protect it from pebbles and stones thrown up from my wheels.


1 comment:

  1. Stone resistance is worthy. I'm with Forester when it comes to rear reflectors. Should that light go out, a big amber reflector will beat a LOT of tape, though this stuff sounds a bit special.

    Perhaps PM can tell us where to find this "department approved" stuff...