Bike safety flags can help keep bicycle riders visible
The greatest risk for someone riding a bike on roads with automobile traffic is being hit by a car. I strongly support infrastructure improvements that physically protect someone riding a bike. Dedicated bike paths and protected bike lanes can help a lot with this.
I don't like putting the burden of safety on the more vulnerable in general. At the same time, if there's a low-effort way to improve safety, it's probably a good thing to do. According to the NHTSA, the 2nd leading factor in bicyclist deaths is "Not visible (dark clothing, no lighting, etc)". Vehicles are getting bigger, which causes more line of sight problems for other users of the road.
Adding a flag is an easy and low-cost way of improving visibility, but it does have a few caveats.
What is a bike safety flag?
Bike safety flags typically comprise of a tall and light-weight pole, with a flag on top. You usually attach the flag on the back of your bike. The flag is often made of a bright color and can flutter around for visibility. The pole increases the height so that the flag can be seen from farther away.
The pole sometimes comprises of multiple segments to make the height adjustable or shipping easier. And the bicycle safety flag pole is often seated in a special bracket that attaches to the bicycle. This bike flag holder often attaches to the axle of the rear wheel. The pole is often made of fiberglass, and the flag of vinyl or polyester or nylon fabric.
Why use a bike safety flag? Do they actually work?
Bicycle safety flags can dramatically increase a rider's visibility. A taller, brightly-colored flag is visible from blocks away. A personal note: One day, we were riding to school on our Oakland Slow Street, hoping to see a friend on the way. I was able to spot my child's classmate from 3 blocks away because I saw their orange kids bike flag waving back and forth. So I can personally attest to how well they work.
Children on bikes are often less visible in general because they ride lower to the ground. So bike flags can benefit children even more. Some cargo bikes, recumbent bikes, and trikes also ride lower to the ground as well. Bike flags for safety are particularly common among recumbent bikes.
Another nice feature of bicycle safety flags is that work passively. They require no electricity, charging, and not much maintenance. You just ride your bike and it works.
What types of bicycles are bike flags used for?
Bike safety flags are most popular in high-leverage situations, where the risk is high either due to rider geometry or the frequency of exposure to risk.
Bikes that are low to the ground
Kids are smaller. Their bikes are smaller and closer to the ground, thus harder to see. Kids bike flags make a lot of sense here for visibility but can cause other issues (discussed below).
The vibrant recumbent bicycle community has a lot to say about bike flags. Recumbents often run smaller wheels than traditional upright bikes, and the rider is perhaps only half as high as a rider on an upright cycle.
People who ride a lot
If you're a utility cyclist and ride to and from work, on errands and so forth, you might want a bike flag. You might have a higher risk of being hit by a car driver just due to how often you ride a bike.
Bicycle delivery riders spend their work time on a bicycle and may be constantly exposed to risk from automobiles.
People who place a premium on visibility and safety
Cargo bike riders, family cyclists, and bike trailers
Parents who ride with their children on board might want a bit of extra visibility because of the increased consequences if hit while riding a bike. This includes traditional bikes as well as cargo e-bikes.
Many bike trailers come with a flag because they ride low to the ground and usually contain precious cargo.
Places where safety flags are legally required
ATVs / Dune buggies
These aren't bicycles, but the flags can be pretty similar. Dune buggies are often required to have flags by law to increase visibility and prevent crashes.
What types of bike safety flags can I buy? What are the differences?
"Traditional" bike flags:
I'm calling these "traditional" because they seem to be the most common type available.
We already had two of them from a bike trailer and a Trail-a-bike. These are made of 1/4” fiberglass poles about 3ft or 1m long with a piece of plastic to connect two poles together. There’s usually an safety orange or hi-vis green flag that goes on top. Our trailers had built-in mounts for attachment. Other flags (as I mentioned earlier) have a metal bracket to attach the flag to the back of your bike.
Multiple brands sell them for about $10-20. They mostly consist of fiberglass rod segments, plastic piece to join them, an orange flag, and a metal bracket that attaches to your bike’s rear axle. Most of them are a variation of one or two different designs.
Some version of them can also be found in sporting goods stores and bike shops. Even Home Depot seems to sell a bike safety flag online.
Some of these flags come in 3 sections, some in 2. They are all pretty similar.
Mini bicycle flags or handlebar bike flags
These are around a foot tall and don’t seem to do much at all. But they’re cheap. They seem to be most useful if you want to use the flag as a display item or decoration. They don't improve visibility much.
Horizontal bike safety flags
Horizontal bike flags are a unique subcategory of bike safety flags. They can improve visibility but also help the rider establish a buffer zone between themselves and automotive traffic. They are kind of a physical reminder of California's 3 foot law. These bike flag poles don't rise above the rider, and so may not be much easier to see from far away.
Take Your Lane
The Take Your Lane is the most adjustable and feature-packed of these "horizontal" bike flag poles. You clamp an aluminum plate onto the rear stays on the left side of your bicycle. It has a bunch of holes for adjustment for different frame geometries. Then one can adjust the angle of the bike flag pole.
Other horizontal bike safety flags
The Bike Safety Stik by Bremor attaches to the head tube of a bicycle using velcro straps. It's designed, like the Take Your Lane flag, to stick out horizontally to create a physical buffer zone between passing automobiles and your bicycle.
The M-WAVE flag ($8) has a ball joint that allows it to stick out horizontally or vertically. It gets pretty mediocre reviews though due to its build quality.
Specialty bike safety flags
Recumbent Bike Flags
There are a lot of really fancy recumbent bicycle safety flags. Many are optimized for long use and high visibility. They are shaped for aerodynamics and visibility over a larger area and often include streamers for added dynamism. They may cost more at $40-60, but are designed to be used for a long time.
LED light up bike flag poles (aka LED whips or Bike Flag Lights)
Bike flag lights (for bicycles, not motorcycles or ATVs)
I've been prototyping some flag pole lights for bikes around the streets of Oakland and Berkeley. They seem to get a good amount of attention. At least we hear encouraging comments from people we ride by, like "I like your light sticks!" or "Those are so visible! They are great!". They are now available for private presale.
LED whips for ATVs
These mostly consist of a thin pole with LED strip lighting wound around in a helical pattern. They make ATVs visible at night. They are powered with a power cable that attaches to the vehicle’s power. Some of these come with apps for changing the color and so on. These seem to cost $60-$150 or more depending on how nice they are. They have a large visual impact but are not practical for bicycles.
What are reasons not to use a bike safety flag? Here are reasons not to.
Bike safety flags aren't for everyone though, and there are some characteristics that may make them not desirable.
Bike safety flags can be too tall
Tall bike safety flags generally make the handling of a bike more difficult. For example, it's hard to walk around a bike with a very tall flag. You need to really walk around it.
Tall bike flag poles can snag
A tall bike flag pole can snag on a low hanging branch, garage door, or a person. Most of the flag poles are flexible to accommodate for this. But fiberglass is kind of springy, so they can whip back around after they snag.
Bike flags can alter the bike's handling
Bike flags can adversely affect the handling on smaller bikes in particular. I tested a flag with my child on their 16" bike once. Kids are not necessarily steady riders, and the flag was so heavy and tall that it swayed a lot from side to side. My child eventually complained that the flag was making the bike "too tippy". We removed it soon afterward.
Bike flags may not match one's aesthetic sense
Purists and minimalists won't appreciate the look, as a bike safety flag will disrupt the bike's aesthetic.
What are some alternatives to using a bike safety flag?
What to use instead of bicycle safety flags?
Traditional head and tail lights
Headlights and tail lights are pretty much a requirement when there isn't much light for seeing and for being seen.
Wheel lights and other non-traditional bike lights
There are bike lights that attach to your wheel and spin as you move. The dynamic light helps catch attention and the lights can be colorful and fun. There are also some decorative lights that one can wrap around their bike frame.
A few clothing manufacturers (such as Shower's Pass) make ultra-high-visibility reflective outerwear that will make one more visible at night.
What I recommend for improving bike visibility the most
Visibility recommendations for daytime use:
I recommend a bike safety flag for children who will be spending a good amount of time on streets shared with cars. I don't recommend it for childrens' bikes with wheels 16" or smaller, unless they are also riding with training wheels. But children who are riding on training wheels are probably not riding fast enough to share a street with automotive traffic. So there's probably a narrow band of kids these flags are good for: those in the 5-8 year old range who are riding on bicycles with 20" wheels.
For bike trailers
I definitely recommend a bike flag for bicycle trailers. This includes the Burley, Thule, and InStep styles where the child is towed behind in an enclosed space, as well as the WeeHoo and Trail-a-bike styles where the child sits in a bike seat and can pedal. Most of these trailers have 20" wheels and are low to the ground.
For night time visibility I recommend:
Headlights and tail lights
Low cost and effective options are easy to come by, as I wrote in my gift guide:
The VONT Pyro set (and most of other nearly-identical lights: Ascher, Jiying, etc) are a great value. They cost from $10-15 per set, are easy to install and are rechargeable. This style of light is surprisingly bright for the price. They are fine for casual riding at night, but maybe not enough if one rides in the dark regularly. I give out a similar light at our bike parades if it's dark (and I sell them on this website as well).
There are many other headlight and tail light sets on Amazon that look identical. The main differentiator here is probably customer service. Look for a brand that gets good reviews. There's always a problem with fake reviews. For these lights, a good review rating and large number of reviews likely means a customer-friendly replacement policy and good service rather than high quality.
You do sort of get what you pay for with the more expensive lights. The build quality is better, they shine better and brighter, and will probably last much longer.
There are other lights that mount on your frame or wheels. Some of them are complete garbage. Others are not bad. Many of them are made in the same factory, or are copies of others made in similar factories in Asia. They can provide some colorful fun at a low cost.
Thank you for reading this guide on bike safety flags. If you have anything you'd like me to add, please email me and let me know or leave a comment.