Deer Avoidance System
Thank you for a fantastic collection of ideas and links, Cameron!!!
I noticed that you are wondering about the effectivness of the "deer avoidance system." The setup you have linked to seems like it would be effective if you are trying to make sure that deer get a bit of warning that you're on the way when they are just ambling across the road, stopping on the tarmac to check for straggling fawns, etc., in an area where there's not usually very much human/vehicle traffic. The "sonic echo," in that situation, might be unusual enough to catch their attention and spook them back into cover. But it could also make them freeze . . . or bolt across the road to reach a thicket . . . or, if you're in an area of relatively heavy traffic, they might just ignore it.
Since I live in white tail deer heaven - the Shawnee National Forest - I'm always on the lookout for 'em and I know better than to rip around a blind corner or crest a hill hard on the throttle, especially around dawn and dusk when they are apt to be on the move. However, the time when they are really unpredictable is during the autumn rut. In the heat of high hormones, does will flee bucks - and bucks will pursue - straight across a crowded Interstate where 18-wheelers and everybody else are laying on their horns and creating a deafening. But the deer aren't fazed by it, not even a little bit!
As far as I'm concerned, the only really effective "Deer Avoidance System" is a combination of good eyesight, a basic understanding of deer behavior and their usual daily and annual cycles, and a whole heap of common sense and throttle restraint when you are cruising through areas where deer are likely to roam. Around a local university campus here in southern Illinois, the deer are so used to human (and vehicle) presence that I've been able to throttle down, glide to stop, shut off my bike, dismount slowly and with a minimum of thrashing around, and take four or five steps . . . to find myself within 5-6 feet of deer grazing on the roadside or crossing it to get at the forage on the other side! Deer love to feed in "margins" - the open areas along a tree line - where they can find succulent treats and can make a quick dash back into the protective cover of the forest. Watch out for them . . . and take it for granted that they may be in the habit of ignoring stuff that humans think that deer will avoid!