
Look out kid
You’re gonna get hit
—Bob Dylan, “Subterranean Homesick Blues”
This spring Dr. Bob in LA wrote to tell me about his latest and greatest. He got a Garmin Varia radar unit and waxed enthusiastic about it: “I recently got a Garmin Varia rear light/radar. There was an article in Bicycling about these radar lights and they picked that as the best one. It works just as advertised and I have had no false negatives in the 3 weeks I’ve had it. By some weird magic I don’t understand, it will show not only one but however many cars are coming up behind you as dots progressing from bottom to the top of the Garmin computer display (on the extreme right side of the screen).
If you don’t already have one, I’ll tell you more about it because you should get one for each of you. I know you always used one of those geeky little mirrors that attached to the helmet. Aside from the geeky thing, I was always afraid that if I crashed and my head hit the ground, the extension stem would be driven into my temple and I’d get a scrambled frontal lobe.”
I’ve also known about radar units for some years now and they have always struck me as overkill…for me. As Dr. Bob mentioned I’ve flown my Fred flag high for decades by sporting a helmet/eyeglass mirror. I do not recall the year I started using one but I had one on my Bell V-1 Pro helmet. So this puts it in the early 1980s and I’ve been a mirror devotee ever since.
Recently my thinking about bicycle radar units has evolved. I now think that radar can be quite helpful as an adjunct to a mirror. Roger recently acquired a Garmin Varia radar unit and actual use has shown me how it can be helpful and where its deficits truly lie. But before I go into a discussion of the radar itself, I need to provide a history of cycling mirrors and how they came to be anathema to most cyclists.

Once Upon a Time…
I’m not sure when helmet and eyeglass mirrors first appeared. Before them we had handlebar mirrors. These were rear view mirrors, made of chromed steel, that you attached to your handlebars with a clamp. My recollection is that you could get one at the Schwinn dealer along with some bar-end streamers. Although my first ten-speed was a green Schwinn Continental, I did not put a mirror on it probably because I didn’t know any better. When you’re 13, you aren’t expected to know any better—as I can vouch from seeing the local tweens do wheelies on their e-motos on my street—and my mom didn’t know how to ride a bike anyway and didn’t drive so she knew nothing about rear view mirrors, certainly not enough to hector me about using one.
When I was a whippersnapper I didn’t know shit about car traffic because my parents wouldn’t allow me to ride in the streets. I rode only on the sidewalks and my cycling interactions with cars were very limited. It never occurred to me that I might benefit from a mirror even if it did look cool on a Schwinn Stingray.

When I was older and interested in racing I learned that there was a technique to looking back. Racers never use mirrors, period. But they need to have exquisite situational awareness—to know where other cyclists are around them as well as who those cyclists are, teammates or opponents. Hearing obviously plays an important role. You detect when someone is shifting, freewheeling, how hard they’re breathing, etc. But you have to rely on vision as well so you have to look back to see where other cyclists are (among other things). The trick is to look back and still continue to ride a straight line. This is a lot harder than it seems. The first time you try this you will find yourself veering to the left (since you turn your head left as traffic is on the left mostly). Veering is generally bad because you end up going places you don’t intend like into the traffic lane. If you’re in a group, veering often results in a crash or at least a lot of shouting as you’re told to hold your line by your irritated ride mates. After a lot of practice I got okay at looking to my left and going more or less straight ahead. But like everything else if you don’t practice you get rusty as I found out recently. I have enough trouble keeping a straight line when I’m looking ahead, so turning my head to look back is not a good strategy for finding out what’s behind me. The irony isn’t lost on me of perchance looking back to check out that car coming up behind only to hit something like a big tree branch lying in the road and then crash.
Nonetheless for many years that is exactly what I did when I was in traffic: I turned my head and looked. When your life depends on it, you become facile at riding straight while pivoting your head. And I turned around to look a lot, in fact every time I heard a car approaching and more! Practice does make perfect. Most of the other cyclists I was around did not turn around to look as much as I did; they mostly relied on their hearing.
Mirror, mirror on the wall, who’s…

At some point I certainly knew about helmet and eyeglass mirrors. They were usually shown on people with Bell Biker helmets, one of the first hardshell helmet produced specifically for cyclists. (MSR produced a hardshell bicycle helmet but it looked like their rockclimbing helmet repurposed for cycling. There was also the Skid Lid, which barely qualified as a “helmet” even if it did have a hard covering. Some folks also used repurposed hockey helmets.)

It’s an easy dance, give yourself a chance
Dance the Freddie (Freddie)
It’s the thing to do, kids will envy you
So do the Freddie (Freddie)
—Freddie and the Dreamers
Wearing a hardshell helmet was the telltale sign that you were a Fred, a “tourist”. Along with your t-shirt, tennis shorts, tall white athletic socks, and tennis shoes, Freds were seen riding heavy pipe gauge tenspeeds (like a Schwinn Continental!) with all manner of crap attached to their bike, like mirrors, bells, lights, racks, and maybe a basket. In contrast cool cyclists wore black wool shorts with a chamois, wool jerseys, had no crap attached to their bikes, used toeclips with Detto Pietro cycling shoes and nailed cleats, and maybe a leather “hairnet helmet” if they were racing (since they were required in the US back then). You rode a Raleigh, a Peugeot, or maybe a Masi, Cinelli, or Pogliaghi if you were really in the know. Needless to say no one aspiring to be cool wanted to be a Fred. Only when hardshell helmets became required to race did their Fred factor decrease.

But I was inexorably attracted to the Fred side. Even if a leather hairnet was mandatory for racing, no one wore them when training. Yet I was one of those kids wearing a leather hairnet on the Portola loop because I knew smashing my noggin was not a good idea. I had no idea how useless those leather hairnets were at preventing brain injury. When the Bell Biker helmet was announced, I got one right away. It was a fucking boat anchor. It’s ventilation was anemic and in hot weather it became a sweat box. It also was the wrong shape for my head. But Bell had the impact research that showed their helmet could reduce the crash forces that turn your brain to jiggled Jello™.
And that’s what led to the helmet mirror. I got tired to turning my head all the time to see what was behind me. Keep in mind that in the Old Days even though there weren’t cell phones to distract drivers, the antipathy and hate drivers held for cyclists was malevolence personified. It was Jim Crow for bicyclists no matter what the pretty Schwinn ads tried to convey about cycling. You got out of the way of drivers unless you had a death wish. We were all gutter bunnies. So despite its Fredliness I started using a helmet mirror. It was a revelation.

I’ve never looked back. (Pun intended.) I put a Third-Eye plastic mirror on my Bell helmet. (I’ve since switched mostly to mirrors that fit eyeglasses.) Using a helmet or eyeglass mirror does take some adjustment. You have to position the mirror such that you can look back comfortably and in the typical positions in which you ride. After you’ve got that nailed, it’s a cinch. I’ve used a variety of mirrors and they all have their quirks. But they all get the job done of allowing you do quickly see what’s behind you.
A mirror is great when you’re riding in a group, not just to see if cars are approaching from behind. A mirror allows you to see who and how fast someone is trying to catch up to you; you can see if you’re dropping those behind you or conversely who’s revving up to launch an attack from behind. On club rides I can keep track of riders in the back or to spot if someone has stopped perhaps because of a flat. You can tell a lot by how a cyclist rides their bike. On the tandem with Dr. Bob I was the stoker and also the “rear” eyes, as Bob steadfastly refused to use a mirror. Bob steered and took care of business in the front and I watched the back for cars and for the inevitable wheelsuckers. We delighted in torturing them. These folks thought that they were getting a free ride by drafting a tandem; we had other intentions. In the mirror I could see how hard they were working to stay on our wheel without giving away that I was checking on them. Then I’d tell Bob to go up a gear or increase the cadence. We’d do that slowly until everybody was blown off the back. Then there were the times we were being kind; if we lost someone, we’d slow down to let them suck our wheel. C’mon, you know! There are times you like to be sucked!
In the forty years I’ve known Dr. Bob he has never used a mirror of any kind. As time has gone on his neck arthritis got worse and turning his head became even more difficult. So the decision to get a radar unit makes sense…for him. Interestingly Bob’s crash history has less to do with failure to look behind than it does with not looking ahead. He was left-hooked in an intersection once and before that collision he once crashed into the back of a car when he failed to notice the car in front had braked. The neck arthritis had something to do with his not looking forward, more precisely not being able to bend his neck enough without pain to look straight ahead when he was hunched over the bars.
Coincidentally to Bob telling me about his new radar unit, Roger’s Cycliq front and rear bike cameras were becoming wonky. That’s not uncommon for Cycliq products particularly with the rear camera. We’ve had two units fail and several of our friends’ units have also died. So he bought a Garmin radar unit, a RCT715, because it had a video camera and a light.

Radar Love
The road has got me hypnotized
And I’m a-speedin’ into a new sunrise
—Golden Earring
Garmin has steadily improved its radar units. Not only has their radar gotten more accurate and a slightly better range but the anemic taillight it originally included has been vastly improved. And now some Garmin units also include a video camera with much of the same utility at the Cycliq camera/lights. The tail light originally was dim, so weak that in my opinion it was useless in daylight. I have been using very high quality lights going back to “Ed Kearney” lights of the 1970s. (You won’t know who Ed Kearney was nor anything about his amazing lights, which were much more powerful than anything you could get back then. The headlight was a repurposed moped/scooter light.) For close to twenty years I’ve been using DiNotte lights, which were some of the first LED lights. I am currently using a DiNotte taillight that emits well over 400 lumens and is so bright that it shouldn’t be used at night. A tail light has to be annoyingly bright to catch drivers’ attention. The Garmin RCT715 incorporates a taillight that I think is quite noticeable in daylight from hundreds of yards. Roger bought this Garmin because of the video recording capability and the lights. The radar was of unknown utility.
Roger also uses an eyeglass mirror although he is not as paranoid as I am and checks it less than I do mine. We’ve discovered that the radar is a meaningful complement to a mirror. There are times when you are either focused on something else and you aren’t paying attention to the rear; perhaps you are avoiding debris in the road or you’re lost in thought or daydreaming. The audible alert from the Garmin is a timely reminder to check your mirror to see what’s behind. If you ride mostly on busy streets, the Garmin is somewhat less effective because you are then getting alerts constantly as each approaching vehicle comes within range of the radar. If it’s too often, then you’re in danger of getting desensitized to the alerts, becoming complacent, and ignoring them. If however you tend to ride on roads with little traffic, then the Garmin really comes into its own because instead of checking back all the time you can rely on the Garmin to alert you to look.
As Bob noted, the Garmin is surprisingly effective when there are multiple vehicles approaching; you get an alert for each one. I was concerned that if I were riding behind his radar, that I would be blocking it from detecting vehicles. This is in fact true but only in degree. When I am behind him the radar is slower to detect vehicles. It does detect them but alerts you with less advance notice. I often ride behind Roger because my tail light is much brighter than his Cycliq’s. But his Garmin rear light is so much more noticeable than the Cycliq’s that I don’t feel the need to do that anymore. In fact it’s better if I ride in front because I won’t be interfering with his radar.
The radar’s audible alert comes from a connected device, either your smartphone or a compatible cycling computer, and not from the Varia itself. The radar unit does not provide an audible alert. So if you ride ‘bareback’, i.e. no cycling computer, you will have to connect the radar unit to your phone in order to get audible alerts. The audible alerts from Roger’s Garmin cycling computer is loud enough that I can hear it over the radio headsets we use to communicate. When I’m riding in front, I can hear Roger’s Varia beeping when there is an approaching car.

With a connected cycling computer the RCT715 provides a primitive visual indicator of approaching vehicles. Each detected vehicle is a moving dot along a line on the edge of your computer screen. If the approaching vehicle is moving very fast, the dot turns red as do the edges of the screen. This is where the Varia pales to a mirror. The moving dot provides an indicator of something approaching you but you cannot discern exactly where or what it is. It could be two lanes over on the left rather than directly behind you. The spread of the radar beam is wide enough to pick up several lanes of traffic. This is a good feature because an approaching vehicle could move over suddenly towards you. But that dot on the line cannot show where the vehicle is other than “it’s back there somewhere.” With a mirror you just look back and you can see the vehicle’s position relative to you, e.g. directly behind you, in the adjacent lane, or two lanes over. You can also spot more finely how close that vehicle is to you—is it comfortably in the adjacent lane, hugging the right edge of the lane, on a collision course with you? You are also able to see how the driver is behaving—is the driver moving in a straight line, weaving, drifting to the right? None of that qualitative information comes through on the radar.
Another limitation is that the radar only gives a rough indicator how far back the vehicle is; there is no scale for absolute distance on your screen to inform you of the exact distance that vehicle is behind you. But by looking you can see if the car is 100 yards back, 75 yards, etc. Furthermore the radar doesn’t give you any information about the nature of the vehicle—is it a car, motorcycle, another cyclist, an e-bike, a lorry, a semi, or a truck with a wide load? Looking in a mirror provides that information. Furthermore you will be able to see if that vehicle is moving over to its left to give you space or overlapping the shoulder/bike lane and necessitating you to take evasive action.

Garmin makes a newer Varia, the 820. The 820 does not have a video camera with crash detection and that was a deal breaker for Roger. The 820 however does have “Advanced Vehicle Tracking”, which gives a bit more information. It now indicates the relative size of the vehicle—motocycle size, car size, or truck size—by providing a different icon for each. It also provides some lateral information—is it to your left, right, directly behind, and is it changing lanes? Clearly Garmin is aware of the limitations of its radar and is trying to mitigate them. We will likely see improvements in the coming years.
By itself the Varia RCT715 just does not provide enough information. However paired with a mirror it becomes useful: instead of constantly having to check your mirror you can let the Varia tell you when something is approaching and then look. In my case I have so many decades of learned behavior on using a rear view mirror that radar provides just a small added benefit. For those of you who are not already using a mirror, radar can take some of the burden off of constantly checking the rear.
I notice that almost all the cyclists I see on the road who use radar do not use a mirror of some kind. Are they turning around to look when they get an alert, or are they relying only on the radar to keep them alive and uninjured? Although I feel somewhat confident in the technology, I don’t feel that the technology can match what a mirror can provide; eyesight is a better technology. That cyclists would adopt radar over a mirror is not a surprise. Tech stuff has cachet and is cool; mirrors are the epitome of Fred-itude. A Garmin Varia RCT715 will set you back about $400. (Garmin does make less expensive radar units plus now there are a scad of less expensive Chinese knockoffs.) A cycling mirror costs about $20. Oh, and I don’t have to remember to charge my mirror. But that’s the price of avoiding being called a Fred. I’m of an age where my age alone immediately identifies me as a Fred. No amount of Rapha, Pas Normal, or Assos kit is going to make me less Fredly. I sport a helmet radio, a helmet visor, a bell, front and rear lights, and ghostly white sun sleeves. There’s no way I can sink lower on the Fredliness scale. A mirror is just a drop in the Fred bucket.
There is one final aspect of radar units that I find disturbing. Although you can rely on audible alerts from your cycling computer or phone, there is merely the crude visual indicator of approaching vehicles. Admittedly practice and forming a habit can speed up your scanning and interpretation of the screen. But hearing the audible and then looking at your cycling computer screen to assess the threat level is not better than looking back in a mirror. The latter takes less time, involves less head movement (for me), and does not demand I switch from far vision to near vision. Depending on where you mount your computer or phone, looking down to see the radar image is likely to be more distracting than using a mirror.
Final thoughts
Does using a mirror or radar really make a difference? That’s the $64,000 question. Certainly using either of these can placate one’s anxieties when riding in traffic. But what we really want to know is if these two approaches actually save lives and prevent injury. Cyclists who ride without a mirror or radar are not ignorant of the dangers of locomoting among cars. They have simply decided that there is nothing they can do and nothing that can be done proactively to keep them alive. In other words, they think the answer to the question is that none of this makes any difference in survival. But it is an empirical question. I’m not aware of any research that’s been done nor have I given much thought about how one would even go about testing the hypothesis.
Approximately 40% of fatal bicycle crashes are caused by drivers rear-ending the cyclist. So being aware of approaching cars and being able to take evasive action could theoretically make a difference in survivability. That all sounds good on paper. But cyclists do not practice evasive maneuvers and are unlikely to be able to respond in a real life situation unless they are forewarned well in advance of a collision. Garmin units can detect a vehicle at about 200 yards. In my area the arterials have a speed limit between 35 and 50 MPH. If a car is going 50 MPH, this means the Garmin can provide about 7 or 8 seconds advance notice. Then you either have to look behind and mentally process the visual information before you can act. So the actual time you have to react evasively is even shorter. I suspect most people will not judge that the car is a danger until it is even closer due mainly to disbelief, so this reduces the time to react even more. None of this means anything if the vehicle is out of control (not uncommon), in which case it’s not clear what you would be able to do to avoid getting hit.
I have found using a mirror helpful in deciding whether I can move laterally—to change lanes, make a left turn, avoid debris, pass another cyclist, etc. There have been a few instances when l looked in the mirror and saw that an approaching vehicle seemed like it would be passing too closely; I then moved over to the right. Of course it may be that the driver would have moved to the left if I hadn’t. But I wasn’t willing to take that risk. I have had a few experiences on narrow rural roads of heavy trucks approaching and it seemed to me they either would not or could not move over; I got off the road. Better safe than sorry.
Ultimately any kind of rear view is insignificant if cyclists are not able to react in time to avoid being hit. Perhaps it’s equally as effective just to pray to a powerful god for protection. Apparently those who were hit from behind and died didn’t have powerful enough gods or perhaps they were being saved from an even worse fate if they had lived. Ultimately it’s like it is with helmets; if you’ve crashed and cracked your helmet, you are probably very thankful you were wearing one and think it saved your head. But a lot of cyclists don’t use helmets despite the data. The data is there that seatbelts save lives; the data is there that helmets reduce serious head injury. Is the data there that mirrors or radar reduce death and injury? Probably not. But I’ll keep using a mirror since it gives me a sense of control albeit control that is more than likely fictitious.








































