High Intensity Reflectors for Marking Night Trails

Ultrarunning Edge Blog

Written by Bruce R. Copeland

Sunday, 06 September 2009 13:06

The 2009 Bear 100 will be using high-intensity reflectors instead of glow sticks to mark the night time part of the course. Ultra trail races have for years used glow sticks to mark the trail at night. While glow sticks do a decent job indicating night time routes, they are abhorrent in many other respects. Glow sticks are expensive; they generate complaints from other trail users; they are environmentally unsatisfactory; and they require a special trip over the course for placement (because of their short life time). Here at the Bear 100, we have been searching for a good alternative to glow sticks, and we think we have found it in the form of high-intensity reflective film or tape.

reflectors

There are actually quite a variety of high-intensity reflective materials available. The material we are using is 3M Scotchlite Diamond Grade 983 reflective tape. A great deal of optical engineering has gone into this and related products, yielding a very high reflectivity even at low light levels (R_A ~ 800 cd/lux/m² at optimal angles) and good reflectivity at low angles from the reflective surface (R_A ~ 300 cd/lux/m² at 45 degrees). This material is also highly durable (seven to ten year life), meaning we should be able to reuse these reflectors for quite a few races.

We will be deploying reflectors as 1/2 in. x 3 in. strips attached to standard plastic flagging. This shape is similar to a glow stick and will hopefully make it easier for runners to make the transition from glow sticks to reflectors. The linear shape should also increase the likelihood that reflectors will still be visible when partially obscured by foliage. These strips cost roughly 13 - 14 cents apiece. In testing, these reflectors are easily visible at 100 yards—similar to glow sticks (see 2_reflectors_at_100_yards).

Reflectors are not a one-for-one replacement for glow sticks. Glow sticks require no other light to be visible, whereas reflectors can only be seen in the beam of a strong light. In fact high-intensity reflectors are most visible only when the light beam originates close to a viewer's head. For example, during testing one of us used a hand-held light at hip height and was unable to see a reflector that was clearly visible to someone else wearing a headlamp. Of course, these days the overwhelming majority of night runners use headlamps or some type of light which can be positioned near the head. We fully expect that runners will quickly adapt to this new reflector technology.

With flat reflector strips, there is also the risk that the strip might get turned in such a way that it will not be visible. To some extent we will get around this problem by simply using reflectors more frequently than we would use glow sticks. Positioning the reflector close to the knot on a piece of survey flagging does a lot to guarantee that the reflector will face in the desired direction. Flagging with a reflector can also be tied at each end or tied snugly around a tree branch or trunk to force presentation of a consistent reflector surface. Reflectors themselves can also be attached to tree bark using a push pin or staple gun. Finally in situations where visibility is critical or needed from multiple directions, three reflector strips can be taped together with packing tape to produce triangular tube reflectors. Flagging can be threaded through these triangular tube reflectors and hung anywhere flagging would normally be used.

We believe high-intensity reflectors will be a huge improvement over glow sticks, and we look forward to seeing what kind of reaction they get from runners.

Comments (4)

My two cents- the reflector strips were awesome. Very, very visible and the course flaggers did a good job putting them where they were needed (at trees after long straightaways, on bundles of grass, etc). Very nice and, for the most part, there were enough of them.

The "reflective" flagging didn't stand out any more than regular orange flagging, at least for me. But the reflector strips more than made up for it.

Jon:

I agree that the silver and orange striped 'reflective' flagging isn't really any better than solid orange flagging. Twelve rolls was the minimum we could order when we were originally testing the striped flagging. So we decided to use it up marking the course.

Unfortunately the elk and cows like to eat orange flagging. This means that in some of the open areas where there aren't any trees, the reflector strips get knocked down or even chewed up if they are attached to the flagging itself. We need to find some better ways to secure the reflector strips to brush so that the strips will remain mounted even if the associated flagging gets eaten.

Bruce

Now that the dust has settled from the 2009 Bear 100, here's what we've concluded about using/mounting high intensity reflector strips.

The most effective way to use reflector strips is to attach them to tree trunks. Pick a trunk that is visible from some distance back on the trail. When you get to the tree, attach a reflector strip vertically using a staple (smooth bark) or a push pin (rough bark). Either tie a piece of flagging on a nearby branch or fold a piece over and staple/pin it under the lower end of the reflector strip.

In open, brushy areas where there are no tree trunks, attach reflector strips vertically to small conifer branches or the tops of weeds using a plastic twist tie. The best way to do this is to make two parallel slits about 3/4 inch from one end of a reflector strip and thread a twist tie through the slits. These units are easy to attach/detach, and they are reusable. Tie some flagging to a nearby (but different) branch or piece of weed.

In areas, where reflectors need to be visible from multiple directions, use a triangular reflector tube. Thread some flagging through the tube; tie a loop in the flagging below the tube to keep the tube from sliding off; and then tie the flagging to a higher tree branch.

Sounds like a good plan. I did see several locations where the reflectors were attached to clumps of grass or bushes and was very visible and won't blow away. You can definitely make it work if the course flaggers do a good enough job.

One comment I heard was that the faster guys sometimes had difficulty seeing reflectors because it was still day and there was minimal (or cow eaten) flagging. The reflectors are very great at night, but not much good during the day. Either way, marking the course is a lot of work.