Question: Can rear radar replace a traditional mirror for solo road cycling? —Chris H.
RBR’S STAN PURDUM REPLIES: The application of radar technology to cycling is a great contribution to our safety on the road, but I’m not ready yet to discard the mirror. There’s a case to be made for using both. That might sound like telling someone to wear both a belt and suspenders to keep their pants up but in fact, neither radar nor mirrors altogether replace the coverage that the other provides. They are complementary rather than competitive technology.
Unlike mirrors, radar remains situationally aware even while the rider is not thinking about traffic, and it alerts you to overtaking vehicles while they are up to 150 yards away — often before you can see or hear them. Some radar units even have lights that flash faster as vehicles approach, making the rider more visible to the driver — assuming the driver is paying attention to the driving task of course.
But radar units can give confusing readings, when, for example, another cyclist or group of cyclists is approaching from behind at a speed faster than you are moving, the unit may “see” them as if they were a car. Some units may also fail to alert you about a car behind you if it is traveling at your exact speed.
A false alarm can occur when riding adjacent to but not on a busy road — such as pedaling on a nearby frontage road — where the main road vehicles will sometimes cause an alert.
On the other hand, a mirror can provide context that radar does not. It enables you to view the actual position and behavior of the vehicle behind you and determine whether it is hogging the edge of the road or giving you space.
For another thing, in heavy or constant traffic, when your radar is providing continuous alerts, a mirror can help you distinguish which ones are warning about especially aggressive or careless driving.
And for one more thing, a mirror will keep working even if your radar battery dies.
You specified using radar for solo road riding, so I am assuming you’re concerned about when noticing overtaking vehicles is all up to you — as opposed to a group ride where other cyclists help with alerting the group about traffic. Solo riding makes it even more important to have every possible edge to stay safe. Whether you’re cycling alone or in a group, you can benefit from both a belt and suspenders … uh … radar and a mirror.
Stan Purdum has ridden several long-distance bike trips, including an across-America ride recounted in his book Roll Around Heaven All Day, and a trek on U.S. 62, from Niagara Falls, New York, to El Paso, Texas, the subject of his book Playing in Traffic. Stan, a freelance writer and editor, lives in Ohio. See more at www.StanPurdum.com.
I’ve used the radar/mirror combination for years and rely on both. In many situations, the radar prompts me to check the mirror in heavier traffic areas. For the most part, in less traveled rural roads , I just use the radar. Also, when riding with a group the mirror is a must have when checking on other riders.
Couldn’t agree with you more, Stan. I’m a longtime helmet mirror guy who got a radar unit a couple weeks ago. They really do complement each other. I find when I’m “zoned out” I sometimes am not checking the mirror as often as I should. that little beep from the radar unit brings me back.
Same, longtime mirror and now run both. It’s the only way to go for the reasons you have stated. Highly recommended!!
Out on the road, I want to know the size of a vehicle approaching me from the rear – and whether that vehicle is starting to move over to the left – from maybe 100 yards behind me. An approaching box truck is VERY different than a motorcycle, especially on a two lane road with no shoulder and oncoming traffic approaching (which deters some drivers not willing to wait for oncoming traffic to clear before passing, from giving room while passing). A radar unit will NOT provide this relevant information, but a mirror will (when adjusted and used correctly). This bike radar technology, though helpful, is not ready for prime time, IMO.
Thanks, Stan, for that well-reasoned perspective. I’ve used and advocated for mirrors for as long as I can remember. You have started me thinking that it may be time to add suspenders to my belt!
One other thing I think mirrors may be better at than ears, and possibly radar, is identifying those objects approaching from behind that are wider than they sound. I’m thinking of “outrigger” mirrors such as the ones on trucks or school buses.
Thanks for the comments!
I will stick with the mirror only. I am deaf and have ridden over 100,000 miles outside on the roads since 2013 as recorded on Strava.
For almost 10 years, I have used mirrors and radar as necessities and consider them complimentary. I NEVER trust the radar to tell me I am clear behind. I always check my mirror to confirm. It is never a question of Either/Or, always both. I have not tested Garmin’s new unit, but it supposedly can give you information on size of the vehicle and lane changes. A new question becomes, are the radar units starting to provide TOO MUCH information and thus distract our attention.
Beep->glance=alert and ready to dodge. I feel naked without both.
I’m a strong believer in using a mirror, but have yet to be convinced of an increased measure of safety from radar. (FYI, I ride rural roads, solo and in groups.). Yes, one can inadvertently begin wandering further into the lane, and a heads up warning here could be useful. Ultimately though, it seems to me that the cyclist ends up having to trust that she is seen by the motorist, and lacking, dare I say, foolproof visibility of the cyclist, I’m not sure ultimately how valuable a mirror or an electronic gadget is. (There are obviously exceptions.). I have taken to using a powerful, strobing tail light (Cigolite Hypershot 350), which I consider to be more-or-less in the realm of foolproof, as even a partially inebriated or distracted, (or both) motorist is liable to be jarred to attention by a light of this intensity at a considerable distance, (not too unlike an ambulance), even in bright daylight. I see far too many cyclists while driving who aren’t wearing bright clothing and are also using puny tail lights, That’s asking for trouble.
FYI the Varia and other radar units are also bright rear flashers and they flash brighter and differently as they detect a car approaching, which tends to catch a driver’s attention because of the change and reaction as they approach.
Well, I guess I have to be the outlier here. I’ve been riding bikes for over 60 years and have never found the need for a mirror, let alone radar. I rely on my ears and a quick glance over my shoulder if I feel the need. Frankly, I would likely find radar to be more annoying than helpful.
To me, your point of view is perfectly understandable, provided that you make a sensible effort to be seen, with a decent tail light and a high visibility jersey.