Pavement Projection Provides Better Bicycle Visibility at Night

Few would question the health benefits of ditching the car in favor of a bicycle ride to work — it’s good for the body, and it can be a refreshing relief from rat race commuting. But it’s not without its perils, especially when one works late and returns after dark. Most car versus bicycle accidents occur in the early evening, and most are attributed to drivers just not seeing cyclists in the waning light of day.

To decrease his odds of becoming a statistics and increase his time on two wheels, [Dave Schneider] decided to build a better bike light. Concerned mainly with getting clipped from the rear, and having discounted the commercially available rear-mounted blinkenlights and wheel-mounted persistence of vision displays as insufficiently visible, [Dave] looked for ways to give drivers as many cues as possible. Noticing that his POV light cast a nice ground effect, he came up with a pavement projecting display using four flashlights. The red LED lights are arranged to flash onto the roadway in sequence, using the bike’s motion to sweep out a sort of POV “bumper” to guide motorists around the bike. The flashlight batteries were replaced with wooden plugs wired to the Li-ion battery pack and DC-DC converter in the saddle bag, with an Arduino tasked with the flashing duty.

The picture above shows a long exposure of the lights in action, and it looks very effective. We can’t help but think of ways to improve this: perhaps one flashlight with a servo-controlled mirror? Or variable flashing frequency based on speed? Maybe moving the pavement projection up front for a head-down display would be a nice addition too.

67 thoughts on “Pavement Projection Provides Better Bicycle Visibility at Night

  1. I am not quite sure if that – rather short distance – red-light-mosaic is giving better visibility than a reflective vest worn over that ALL DARK CLOTHING would provide.
    For many years I have been walking and bicycling in the dark. In my personal experience, any light experiment does NOT help make car drivers more observative. BRIGHT reflective clothing does.

        1. Probably a macabre joke, but target fixation is definitely a real thing. Especially with drunk drivers. Sometimes being ultra-visible just attracts them to you like brain-dead moths to a light.

          But that’s hopefully a niche scenario. for the most part, more visible is better. And more audible too, although the loud pipes crowd is much more controversial. Hey, it works for ambulances. It’s a kind of antisocial behavior to put one’s safety above the peace and quite of the whole world, I suppose.

          1. Target Acquisition is even worse!

            Drivers are self-trained to follow the red lights ahead of them. Even worse in bad weather, as they’ll continue driving when they can’t see properly, trusting/hoping in following the red lights. See red, Acquire Target, Target Fixation, follow it. Only they’re driving faster than the bike.
            Flashing lights at the back attract their notice even more. This is extremely worse for DUI.
            Some jurisdictions in Europe ban flashing rear red lights.

            I live in a city of 1.3 million. Driving my bike after midnight in the dark on the street, rear red light with front white light. Cops stop me and tell me to turn the lights off, drive on the sidewalk, so the DUIs don’t run me over. If they see me, they’ll drive where they’re looking, or follow the red light(s). Dark on the sidewalk, they’ll be passing me before they see me, if they see me, so my chances are far far better to not get hit.

      1. That 3M reflective stuff borders on magic – it is very cool. As a cyclist who dodges ninja joggers on the trails in the early morning hours, I have one complaint against it: It instills a false confidence resulting in people not carrying a light or at least wear bright clothing.

        The problem with the trendy dark coloured jogging outfits that have this 3M reflective material, is that it is _only_ visible if my headlight directly paints you. And lots of cycling headlights are quite narrow in their beam. In other words; if you are coming in at a right angle to my trajectory – I CANNOT SEE YOU!

        If jogging at night, a bright blinking arm / ankle band visible from both in front and behind you is much preferred.

        (Oh, and taking your dog with you, light up the collar too!)

        1. Dog walkers are right fun. They walk on one side of an unlighted bicycle lane wearing dark clothing with their dark coloured dog across on the other side of the lane and in between a nice stretch of leash!

          1. It does not even matter much if it is light or dark. From my rollerskating experience – when you notice a thin leash, the braking distance is already gone.
            The only thing worse is little kids – they tend to run to their parents, right across the lane, not to the safe side.

        2. What you want is Retro-Reflective material.
          Like most modern traffic signs, it reflects the majority of the light reaching it directly back at the source, maintaining the maximum brightness possible.
          Which is why your bike light shouldn’t be just a narrow beam in front of your wheel or out in front. It should be like car headlights, with the majority of light on the road ahead of your for some distance, but also with light filling in beside the path of the vehicle, as in, including the shoulders and ditches. That wider part of the beam will catch the retro-reflective material on clothing, bikes, etc..
          If you need to, a beam light on the road and a dimmer wide light to light up what you were missing.

          If you really want your bike to be seen, put some retro-reflective strips on the rims (or in the cutouts, if they have them). Show movement and direction of movement.

        3. In the past before LED headlights the lights were designed to show what was in front of the cyclist, now that it’s all LED, oddly enough, they are designed to just be a bright spot for others to see and make little or no attempt to help the cyclist see ahead. I guess it’s the result of old light bulbs being easier to use with a reflector to get a directional beam? Or is it about expecting all roads to be well lighted? Or is it just that once designers thought more about an objective and now it’s more about some random guy making something cute and/or cheap?

    1. “I am not quite sure if that – rather short distance – red-light-mosaic is giving better visibility than a reflective vest…”

      Agreed. But… it’s sooooo less dorky looking!

      “…over that ALL DARK CLOTHING…”
      Yah! I really do hate that. There are far too many pedestrians out at night where I drive that love to wear all dark clothing. I don’t have much sympathy for people that do that but I certainly don’t want to be the driver to hit one!

      But… expecting everyone to walk around looking like a crossing guard… yah, that’s not gonna happen either. (sorry crossing guards, thank you for you work, we do love you! I don’t dress in anyone else’s work uniforms on my off time either.)

      I wish people would consider the utility of wearing brighter clothing when walking or riding at night. But… if achieving the same level of safety can be done with either ground lighting or a reflective vest… It’s the ped’s choice but i can certainly see the appeal of the ground lighting.

      1. I think the best effect is a bright red rear light that is consistent in design across bicycles so the other road users can get used to seeing an expected pattern.
        That won’t happen though, but theoretically I meant.

    2. The WORST problem with bike lights are the people who use Ultra Bright LED Headlights that blind people like me riding in the opposite direction. No one using those LED Headlights care about focusing them no more than 20 feet ahead – they’re focused down the road blinding people who have to look to the side until they pass.

      Think of drivers of cars with their highbeams on. That too is a long standing distraction from dumb drivers who don’t know any better.

      1. The worst yet from high-brightness lights pointing at us oncoming is those that also blink at epileptic-inducing rates… or when the blinking tricks the mind into thinking a car is appearing and disappearing in traffic next to a blind cycle-route bend.

        That last one is what caused myself to crash into another cyclist, I had no sense of orientation and was distracted by the phantom blinking car that turned out to be the mentioned cyclist. None the less I had a right go at him about both the blinking and the blinding height being the cause of the crash.

        Before and after the incident I’ve had too many near misses and nearly went off a few ledges due to stupid cyclists (Usually they’re racer-bike type owners and normally in spandex race-gear), one ledge that seemed over 30ft on what looked to be a 75 to 80 degree hill (just a guess, night time impairment of judgement).

        1. Yep. I forgot the blinking lights – DISORIENTING – and again I am forced to look away, not in the direction I’m traveling, to avoid the ON/OFF/ON/OFF/ON/OFF/ON/OFF BRIGHT light.

          A definite Hazard.

    1. Now that was exactly my first thought. Though I fully understand this project and I must say that the effect on the photo looks nice I’m not sure if it is/was a good idea. One cyclist with such a system is confusing… eh… what is that?!?! may drivers wonder. While many of these cyclists riding through town WILL induce a horrible confusing field of mixed patterns that make drivers feel like they are driving through a kaleidoscope instead of town.
      I can only hope that this cycle guy doens’t cycle in my neighborhood because his heavily distracting lights might cause drivers to avoid him but this could result in steering towards me (if I would happen to be at the wrongplace at the wrong time).

      I use normal lights that function fine and are according the traffic laws. This way drivers know what to expect when the meet me on the road. Although my clothing isn’t always as bright and reflective as it could/should be.

      In the mean while I would like to suggest to remove these (possibly) illegal home-brew x-mas lights and avoid this potentially dangerous road as much as possible. Please be careful out there.

    2. Interesting.

      In my country red and blue lights are not allowed as that is for police. Flashing yellow or white lights are common on non emergency vehicles as a way to be more visible in fog. Usually one only sees those on commercial vehicles and school buses but I’m pretty sure anyone can do it. Also yellow lights are common for personal vehicles that tend to stop a lot such as newspaper delivery.

      Fire trucks and ambulances use flashing red lights here. Maybe putting a large flashing red light on top of a car would be a problem as it might be confused with one of those. I’d have to look it up.

      It’s not like flashing red lights aren’t all over the road though. Dirt common turn signals, found on every vehicle are flashing red lights! Also there are tons of commercially available lights for mounting on bikes that are flashing red. There are even flashing red lights that are marketed for holding in ones had or strapping to one’s arm when running or walking. Here flashing red is the second most common color at night, exceeded only by the steady white of the headlight. Is this not how it’s done everywhere else? Do joggers and bikers use some other color to stand out? I can’t imagine this being an issue.

    3. I am a fan of the ground effect lighting which is constantly on and surrounds the vehicle with a nice looking and easily seen halo on the roadway. I am adding some to my 50cc scooter because it seems a lot of folks do not see me when I ride at night…of course, most of them are texting at the time.

    4. NSW bicycle laws…

      “Bicycle riders must not ride a bicycle at night or in hazardous weather conditions unless the bike displays a flashing or steady white light from the front, and a flashing or steady red light from the rear. “

  2. I’d love to see how well this actually works, and whether it increases confusion on localizing the light source.

    Blinking LEDs are generally horrible to indicate the locations of objects. The human visual system just doesn’t work well with that hard on/off stimulus. The eye registers the blink, and naturally tries to track it, but then it’s invisible. It’s impossible to nail the location of the blinkenlights without several blinks, unlike the old slow-on-slow-off filaments.

    One of the worst offenders of this is the modern LED automotive turn signal, and even brake lights. Instant-on is great, and decreases response time compared to the old slow incandescents, but when they instantly wink out, the eye can’t localize them at all. It’s distracting and confusing. (maybe that’s why so many people don’t use them these days :-\ )

    It is easy to implement a slow (like 200 millisecond) fade of blinky LEDs, and make their conspicuity so much better. Curses to the implementers who don’t do this, especially on safety-critical systems like turn signals.

    1. Extensive research by Muppet Labs™ here on the dark, rainy streets of autumn will back this up – autokinesis makes the localization of any point light source difficult and an intermittent one even more so. particularly from the cockpit of a vehicle with a well-lit instrument panel. The best solution so far has been a “mixed mode” light – one with a constant light plus a flasher (many are built this way) that allows for location and may get attention.

      Unfortunately most of this is for naught when the drivers are more interested in their social media presence than in your mortal existence – that faint glow from a tiny screen is the worst culprit of all of them.

  3. Reflective tape on your bicycle, reflective high-vis clothes and a solid red led light on the back. in the Dusk and dawn the idea is to be bright but to not overly draw attention and possibly distract drivers. Other than that the best way to not end up being a statistic is to ride defensively and always be aware of your surroundings. that and always ride with a recording device to catch bad drivers (hint, put it up on youtube when you catch them)

  4. I agree with others that blinking / flashing lights are more of a distraction to vehicle drivers and other roadway users. High visibility clothing and solid LED front and rear lights are effective. Add orange side markers on your bicycle and all 360 degrees are covered.

  5. Unfortunately, this is one of the places where our legal systems have failed us. Cyclists should not be allowed on any motor roadway more than two lanes wide or with speed-limits above 15mph. They are a hazard to themselves and to the motorists and riders paying for the roadway. There are plenty of routes designated specifically for unpowered cycles, plenty of sidewalks, and plenty of other forms of transportation. I also find it frustrating that cyclists somehow believe that they have the moral upper-hand because they might be more environmentally-friendly.
    If you use public roadways for transportation, then you should be required to follow all traffic signs and signals, have licenses for driver and vehicle, maintain the minimum speed limits, and pay similar insurance rates.

    1. heh, tell me more. Do you have a problem with kids being on your lawn too? Where can I find a road with a 15mph limit? Have you ever seen how little road maintenance the gas tax buys? Or did you know that it hasn’t been raised (in the us) in more than 20 years? I find it frustrating that you somehow think that because you buy some amount of gasoline you can decide what our government does with all of our roads.

      I agree with you that all road users should follow the law, and potentially that all road users should pay insurance rates commensurate to their risk. Much of the rest of what you said doesn’t hold up to further analysis.

    2. you do realize that the problems in your location are not indicative of problems around the globe?

      I am also sorry that you have such problems with how other people think affecting your way of life (regarding your moral superiority comment). When people live in cities they need to learn to cooperate and live together, this includes compromising in most situations which looks like something you are unable to do. I am sorry that we cannot all live to your expectations such that you feel that you are morally superior in your viewpoints and yes i am calling you a hypocrite.

  6. Just get a proper rear light. Not one of those tiny pin prick lights, not something fancy that will inevitably be unfamiliar to people with dangerous consequences. Get a good and proper light that doesn’t blink and with topped up batteries. It’s the best thing you can do.

  7. So when he takes the lane as he should be doing, and those lights shine into the opposite direction lane of traffic, what then? What use are these lights when he’s actually riding the way he’s supposed to be?

    1. Oh, stop it. This false opposition is part of what gets people killed. Motorists are not the enemy. Cyclists are not the enemy. You share the road and both are responsible for getting yourself *and* the other home safely. Even when the other is acting like a moron it’s not about right or wrong or ‘that other group’. Be the smarter one of the two, slow down and make sure everyone is safe.

  8. Sharp flashes look like a random glint or reflection off something, store windows, parked vehicles, etc. As mentiond, they are harder to track. So they tend to get filtered out. We look for the constant presence of something first.
    Also:
    There’s a reason the cuttlefish uses a similar flickering light show.
    When you read why they do this, you’ll understand why blinky lights and or motion patterns are not a good idea.

    Nothing like having the entire streets turned into a 1970’s Disco.
    Are we allowed to be stoned to go with this light show? ;P

  9. I question the benefit. My commute is about 40 miles each way surrounded by cars doing 80 mph. A bicycle would not make it 10 miles before becoming a smudge on the roadway.

      1. He’s questioning the health benefit of riding a bicycle to work which the author said, “few would question”. And he is right. Bicycling is many times more dangerous than automobile travel and automobile accidents are a leading cause of death and injury. Overall, bicycling in traffic is a significant net negative health-wise.

        1. That’s blatantly untrue. If you look at the following link, you’ll see that traffic deaths (including people driving cars) are way down the list with 2.09% of the total. Many of the more deathly conditions above it on the list are health related and in a fair few a sedentary lifestyle is a huge risk factor. Heart diseases (29.34%), cardiovascular diseases, cancer (12.49%), they’re all much more likely than road accidents and your chances of dying from them are all dramatically increased if you’re overweight or obese.

          https://en.wikipedia.org/wiki/List_of_causes_of_death_by_rate
          http://scienceblog.cancerresearchuk.org/2016/10/11/the-second-biggest-preventable-cause-of-cancer-being-overweight/

          However, you don’t have to take my word for it. An expert in the area disagrees and considers the net health benefits of riding a bicycle to be about 9 times greater than the risk.

          http://blogs.plos.org/obesitypanacea/2010/09/07/do-the-health-benefits-of-cycling-outweigh-the-risks/

  10. I’m of the opinion that any light is better than no light at all. I remember the bike lights I had in the late 60’s and 70’s as a kid. Incandescent flashlight bulb, not very powerful, but it at least allowed a driver to see that there was something there.
    Also, wherever utility work was being done, they used to have lights powered by 2 6v batteries that flashed once a second.
    These fast flashing LED lights are in my humble opinion able to get your attention, but then the brain takes a second to
    figure out what it is. Especially for older drivers, the fast flasher can be confusing for a moment.
    Back then too, car lights were yellow incandescents, not very bright compared to today’s white LED headlights.
    They can overwhelm the old incandescents easily. One thing I did see that I find interesting is the rear tailight with
    the laser lane marker built in. It basically says, hey, keep out of this lane to avoid striking the bicylist.
    My only concern is the white LED lights from cars would wash these out making them hard to see.

    I think they’re unobtrusive meaning they don’t shine directly into the eyes of a driver and give a driver a best guess
    idea where a cyclist is especially if the cyclist is wearing dark clothing.
    A reflective vest is a good idea, especially if it’s foggy out. Here in the Pacific Northwest where it can get dark quite
    early in the winter, a steady rear light is your best bet as well as orange turn signal lights.
    Hand signals don’t work well at night.

  11. The next time you go to a movie theater sit at the extreme right or left of the screen. Enjoy the true bright projection? Those laser light “lanes” have no visible effect to the driver in a glass caged boat especially when the road is even damp yet alone wet. Ditto if projecting a flashing “video” on the road in front.

    I have to give way to a cyclist using the stinkbug of headlights, a strobe mode! Just don’t pull up behind me any situation, I have a rear-vue mirror, best safety gear to have.
    This aint your disco, it’s trip-in alley.
    Most here posting seem to agree, just get lit up like a legal motor bike. LED’s and lithium make it easy. I use an 1100 lumin LED ($17) work-light on front only with a flood angle that doesn’t blind oncoming and casts a gob of light down that marks my space even from the rear as well as lighting glass strewn sand bars this time on year. Not the best but 1100 lumin makes the lane open up like you’re another car.
    That cuttlefish is the best argument I’ve seen yet, look up dazzle ca. WW 1.

  12. I agree, the flashing lights are a distraction to drivers. I don’t drive myself, so a bike is my best bet.
    A steady light in the rear is less of a distraction. Naturally, the motion of the bicycle due to pedaling will make that
    steady light wobble a bit. I don’t see the need for all the fancy flashing lights, but like I said in my previous reply,
    those laser lane markers are nice, but having flashing lights directly in the driver’s line of sight is clearly a distraction.
    Overly bright lights are also a distraction .As long as I can see the road, and drivers can see me that’s all that matters.
    A reflective vest is also a good thing. And the best part about that, no batteries.

  13. Cyclist who did 4,700 miles last year in Seattle. Cycling at night with a solid back light and front light is OK but what really helps is a head mounted headlight/backlight. I’ve seen lots of pavement projection solutions but have yet to find one that works on wet pavement. Also its a distraction to drivers since its not familiar to them. My advice from lots of cycling – keep it simple. Night time use a solid light and during the day using blinking lights if you wish. Night time riding is interesting and can be safe – less cars and you in many situations you have better visibility – however aggressive, reckless or drunk drivers are a big issue at night – no light will help with that. The best way to aid in being seen for me has been my helmet light due to its increased height to beam over parked cars. For the cyclist haters – I own two motorcycles and one car. I pay my fair share of road tax and then some. The truth is that a small minority of drivers and cyclists are simply angry people and can’t get along. Lets not let them define everyone. I have encountered plenty of courteous drivers and cyclists. Keep it safe out there.

  14. Well, Seattle has some nice areas to bike. The Burke-Gilman trail is one. There are plenty of ways to get around without having to deal with traffic. There are times that cyclists have to deal with traffic, and you’re right Jay, no light or signal will prevent a drunk driver from turning you into hamburger. Still though, high visibility is the key.

  15. I figure the best way to get a drivers attention is to wear a vest covered with cell phone displays, all showing text messages, Facebook posts, Pinterest items and funny cat videos.

    1. Best answer yet!
      – – –
      Now Wait a second here…
      You wear a backpack containing take something similar a Stingray cell tower spoofer.
      You have it blank the distracted phone users screen & switch it over to your backpack mounted display screen.
      Using antenna triangulation to return the display to the phone screen, once it has passed you.

  16. Do your best to control what you can control. May the force be with you! But looking at those Russian dashcam videos, at the end of the day, you can’t fix stupid… If a car driver is gonna take you out… it might only be your awareness, quick wits and reaction that save yourself. Build the right habits… watch side view mirrors so you don’t get doored, be aware… be very aware. Draw too much attention to yourself…. well… car drivers hit what they are looking at! That parked police car… that tree that suddenly jump out in front of them. Trust no one!

  17. No video, just the still and the description, but does this seem like it will be like the fired series of lights that instinctively guide planes to hit straight down the runway at night? Target Acquisition, Fixation, and guide you right in…?

  18. I’m old, so my eyes really hate any kind of clever flashing or funky light scheme, especially if there is oncoming traffic or commercial lights along a road ahead of the cyclist.

    Best practices would be use a moderately reflective vest and a white light aiming downward from the rear to illuminate the cyclist, cycle, and surrounding road, as in casting a spotlight on the whole scene in a way that the driver’s brain can easily see “cyclist” and not “low-flying ufo.”

    1. Thanks.
      People seem to over-engineer and complicate stuff because it’s the new hipster trend to make some indigogo crap for bikes.
      They are a ROAD VEHICLE and they SHOULD have the same rules as every other vehicle.
      STATIC LIGHTS for godness sakes for all directions and NEVER pointing up. Nearly every second cyclist I encounter has their crappy bright lights directed right into my eyes – as an excuse “to be visible.” Yeah but then I can’t see the road and the rest of the traffic.

      Scooters, Bikes, Cars, Trucks – EVERYTHING has to have red static back light, white static front light with LOW beams and seperate high beams. Everywhere in the freakin’ world. But cyclists are the special snowflake that can do everything.
      Regulate them. Give them license-plates for goodness-sakes. Make them obey rules. Otherwise they are anonymous and can’t be tracked. And this is the reason nobody cares. BEcause who gives a flying crap what I do? They don’t know me. Slap a license-plate on there and they will behave. Because then they are not a black clothed cyclist with a silver bike anymore.

      Give them a regular vest with proper reflective materials and you’re good to go.
      Engineering and tinkering where it belongs. But sorry – I wouldn’t trust my OWN invention to safe my life! Think about that for a second before you slap you own coded arduino for POV-style on your bike “to be safe”….

  19. Spoke reflectors, guys, spoke reflectors.
    I could puke when I see people in black clothing riding black bikes without reflectors.
    When they cross a street at night, or during rain, they’re nearly invisible.
    That’s suicide.

  20. Okay without touting the same stuff others already did – blinking stuff is horrible.

    But:
    Does ANYONE think of light as a problem?
    When you project ANYTHING on the pavement wiith some little flashlights, my Full-LED Headlights or High-Beams will destroy that. Have you EVER driven a new car with full LED or even Xenon headlamps on a highway next to one with Halogen lamps? Their “yellowish” light cone is completely annihilated on the street and only your bright white light stays. Same for the Xenon headlamps. And I can’t think of any way that these flashlights will be brighter and more prominent than my headlamps.

    1. Although the objective is for bike lights to illuminate the road so the cyclist can see where they’re going,
      the other objective is to show that there is a cyclist in the roadway. It’s not a matter of the fancy high powered
      LED car lights overpowering the cyclist’s light, the primary function of a front light is so the cyclist can see the
      road. The secondary function is for the light to be seen by drivers.
      It’s easier for a driver to see a light in the distance before the cyclist becomes visible in the cone of the driver’s
      headlamps. Should a bike be lit up like a Christmas tree? Nope. Steady light in the front and rear.
      Those little turn signals are a good idea since a hand signal may not be seen in the darkness.

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