Project Flock Tail Light Review: Not Your Average Red Blinky – Hailey Moore | The Radavist | A group of individuals who share a love of cycling and the outdoors.

When it comes to increasing cyclists’ visibility, and thus safety, max lumens and fluorescent colors don’t tell the full story. During the five years they spent bringing their flagship tail light to market, the founders of Project Flock combed the research to uncover what factors increase drivers’ awareness of cyclists from farther away. They funneled their findings into the design of the Flock Light, a feature-rich tail light designed to signal “cyclist ahead” in drivers’ brains earlier. In her Project Flock Light review, Hailey Moore explains the most important factor in visibility for cyclists and how this innovative tail light is designed to maximize it.

Conspicuity is kind of a funny word. It’s a term that I have only come across in research relating to the visibility of pedestrians and cyclists. Unlike the somewhat negative connotation of its related adjective, conspicuous, conspicuity is a quality that all cyclists should strive for. But as the founders of the Australian-based company Project Flock discovered while doing R&D for their first product, the Flock Light, cyclists need more than a bright blinky to be seen by motorists. Through a concept called biomotion, the team behind the Flock Light realized that being literally seen needed to translate to being existentially seen.

The Flock Light Design Solution: Signaling Biomotion

Project Flock co-founder Tim Ottaway started designing the Flock Light as an industrial design student in 2019. As a cycling enthusiast and dedicated rider, he was unsettled by research that found that drivers often fail to immediately recognize cyclists as human when the latter ride with a single point of front and/or rear-facing light. While certainly concerning, this makes sense as I can personally attest to seeing a distant beam while driving and not being able to readily discern what the light is; in other words, seeing a red light cutting through the dark isn’t the same thing as registering a cyclist on the road. Ottaway’s design intent behind the Flock Light aimed to change that through a concept called biomotion.

Defined, biomotion is the evolution-driven ability to quickly recognize the movement patterns of living things. For biomotion to click in our brains, we need to be able to see a few different points on the figure in question to register the pattern of movement. That’s where Ottaway would say that most red blinky lights come up short: while they provide one point of illumination, they don’t often signal human motion.

Ottaway designed the Flock Light to differ from other tail light offerings by implementing three beams within the light, when set in either of the two highest settings, Solo Biomotion and Group Biomotion. In these modes, the Flock Light not only pulses the traditional central red LED light, but it also casts light onto the riders legs via two supplementary beams that are angled slightly down and back at the bottom of the light’s body. As a result, drivers are able to see not just an isolated blinking red eye, but also the spinning motion of the rider’s legs. Research has suggested that this visual processing by the driver should register the image ahead of them as a cyclist 5.5 times more quickly than lights that are not equipped to signal biomotion.

Work on the Flock Light began six years ago and the light and mount designs underwent innumerable iterations before being all but finalized in 2022 (notably, winning the 2020 Australian James Dyson Award along the way). Then, for nearly two years Ottaway and Project Flock’s partnering co-founder Marie Penny looked for funding sources to bring the product to life, ultimately running a successful Kickstarter campaign and officially launching Project Flock with the Flock Light in spring of 2024. The Flock Light currently retails for $89.00 USD.

Flock Light Quick Hits:

Research-backed design that illuminates riders legs
Claims to increase visibility by drivers up to 5.5x sooner
Bright Rear facing LED with engineered optics
Battery Gauge that shows battery and charging status
USB-C Rechargable
Waterproof to IPX6
Four Modes: Solo Biomotion (Run time: 4 hr); Group Biomotion (6 hr); Day Flash (12 hr); Eco (100 hr).
Brightness: 5-120 lumens depending on mode
Includes Multi Seatpost Mount and extra straps
Compatible with standard, aero and d-shape seat posts
Price: $89.00 USD

Flock Light Review: Features and In-Use

Compared to a couple of other tail lights I had laying around, out of the box I noticed that the Flock Light is a bit larger. The additional surface area makes sense when considering the pair of supplementary lights at the bottom of the rectangular body. The Flock Light also features a recessed USB-C charging port whose cover fits snuggly and is then further protected from direct tire spray by sitting above the mount attachment point.

One neat feature I noticed when I first plugged the light in to charge is the small string of charging indicator lights that appear across the top of the light body. The estimated charge time to completely juice up the Flock Light’s battery is 1.5 to 2 hours, and the band of indicator lights lets you know the battery’s status. The indicator lights are also illuminated on the first click of the power button so you know how much life the light has before deciding on which setting to choose (more on the different modes lower down).

The (included) Project Flock Multi Seatpost Mount was also an example of extra attention paid to design that I especially appreciated. The mount includes three rubber straps for compatibility with seatposts of different diameters, and the base that attaches to the light. The base is made from a 3D-printed nylon compound and mates with the light body via a similar quarter-turn design used on many bike computer mounts. I love this interface as I’ve definitely snapped off the plastic clip attachment on more than one lesser tail light. Project Flock also sells the Multi Seatpost Mount separately ($13), so you could feasibly have the mount on a couple different bikes, then easily swap the light between them as needed. As a final call-out, the back of the seatpost mount is beveled to help offset a certain amount of the seatpost’s back-leaning angle, thereby holding the Flock Light in a more vertical, and visible, position.

When you’re ready to roll with the Flock Light, it has four modes to choose from: two night-time modes, and two for day use. A short press of the power button illuminates the battery indicator lights, a long press turns the light on to the first mode, then short presses cycle through the different; a final long press turns the light off. As you might expect, the two night modes are the two brightest and feature more limited run times. These are also the two modes that use Flock Light’s innovative lower “biomotion” lights to illuminate riders’ legs: Solo Biomotion, the brightest setting uses a flashing central light, full strength biomotion lighting and has a run time of four hours; the Group Biomotion setting employs a solid central LED light (so as not to blind your fellow riders), half-strength biomotion lighting and has a six-hour run time.

Research has found that using a flashing light even in daylight increases drivers’ awareness to cyclists sharing the road. The Flock Light’s day-time modes use lower-lumen red LEDs for the central light to maximize run times: the Day Flash sends out an irregular LED flash for up to 12 hours, and the Eco Flash emits a low-light but high-frequency flicker for an impressive run-time of 100 hours (tested and confirmed).

Eco flash day-time mode (left) versus the Group Biomotion mode (right).

In use, I found the Flock Light to be an impressive upgrade to other tail lights I’ve had. For starters, I immediately appreciated the consideration that went into the mount, which makes the light super easy to swap between bikes, or to bring inside for the night to charge, and it seems more resistant to breaking than some other designs out there. The battery indicator is also a feature I found very relevant as I’ve absolutely grabbed a tail light while running out the door to squeeze in a ride, only to find that the battery was all but dead.

The Flock Light’s max brightness of 150 lumens seemed to be just above average of what I saw among competing products, but I think the real difference in the Flock Light’s performance can be credited to the increased size of the overall light body and Flock’s signature biomotion lighting. While many brands seem to tout maximum lumens as the most important factor, even leaning into terms like “blinding” as positive attributes, I did find the way that the Flock Light’s biomotion settings created a broader orb of light helped me more quickly distinguish a rider up the road, rather than just a strobe of bright light.

The closest comparable product I found to the Flock Light is Knog’s Big Cobber rear light ($89.95), which boasts 330° of light, with a max output of 270 lumens in two different flash settings for either 2.5 hours or 6.5 hours (it is also waterproof and USB rechargeable, though the charge time is about double Flock’s and the Big Cobber has a more binary battery indicator). I haven’t tested it, but the Big Cobber’s rounded face does appear to cast some of it’s light back towards the riders legs; Knog positions the 330° design as a feature that makes cyclists more visible from different angles, say when turning through intersections, rather than in the context of signaling biomotion. Finally, the Big Cobber does not cast any of its high-powered LED down only out, the bottom of the former’s body is made of flat plastic. Knowing that many brands use the principles of biomotion to inform where reflective detailing goes on apparel, often placing high-viz stripes on the back of the calf of full-length tights and bibs, the down-angled lights of the Flock Light seem ready to amplify other efforts at increasing cyclists conspicuity.

During my first mountain bike race at the end of last year, I had an opportunity to put the Flock Light’s waterproof capability to the test: there were three shallow creek crossings on the lapped course and after ten laps, so a total of 30 instances of splash exposure, I saw no issue with the light. My only real critique of the design is that I found the flat-lying power button hard to find while riding in think gloves.

In Closing

Being winter in the northern hemisphere, it’s the time of year when I never leave for a ride without a tail light. The higher potential for gray days, surprise snow showers, and getting caught out after dark (due to inclement trail conditions, extended toe warming at a coffee stop, or just my general, perennial underestimation of ride duration) combine to mandate a little extra visibility insurance. Or, conspicuity insurance if I want to deploy my new vocab word. With it’s research-backed design, battery gauge, and long run times, the Flock Light has added the peace of mind I need to keep riding through winter.

Pros

Innovative, research-backed design that leverages biomotion to increase conspicuity
Neat features like battery indicator and quarter-turn mount design
Waterproof

Cons