Bike Alert Tells Drivers To Back Off

Bicycle commuters are often in a battle with drivers for space on the road. [Hammock Boy] does all of his commuting on two human-powered wheels, and is quite interested in not getting hit by a car. He decided to ply his hobby skills to build a device that helps keep him safe. It’s not just a tail light, it’s a sensor that shines brighter the closer a car is to the back of the bike.

The sensor portion is the ultrasonic range finder seen in the center of the protoboard. Surrounding it is a set of LEDs. Each is individually addressable with the whole package controlled by an Arduino. The sketch measures the distance between the back of the bike and whatever’s behind it. If there’s nothing, one Red led is illuminated. If there is an object, the lights shine brighter, and in different patterns as the distance decreases.

Certainly the next iteration could use a standalone chip without the need for the whole Arduino. This could even work with two battery cells and no voltage regulator. We also think the use of any other color than Red LEDs is suspect but we do love the concept.

79 thoughts on “Bike Alert Tells Drivers To Back Off

  1. “Oh, I wonder what pattern will show up if I get REALLY close?”

    Nice project. For version 2.0 I’d try to design the LED pattern to imply “back off” rather than “stare at the pretty lights!”. A car horn that goes off when people are too close would also do well, just be sure to have provisions for it not going off when at a standstill!

  2. From my experience, bicyclists plow into a car as the car is making a right turn, never directly head-on. There are drivers who are drunk that plow directly into cyclist, but I don’t think this device will protect you from that. If you really want to protect yourself, ALWAYS wear a helmet.

    1. Ahh. . . yes, I like to call that the “right hook” and it is my reason do avoiding bike lanes which invite that sort of accident (IMO).

      It’s great to see people trying to come up with devices improve visibility; this idea is certainly novel but it won’t be of any help if the driver has their eyes on text message.

      – Robot

    2. There are also a plethora of douchebags who think they must tailgate anything moving slower than they are, regardless of the danger that could pose to the other vehicle.

      1. They’re tailgating you because you’re peddling in front of them in a speedzone where they could be going 25 mph if it wasn’t for you.

        What for a bicyclist is blazing fast, is crawling speed for a car. It’s especially annoying if you drive a manual and have to crawl behind some sunday cyclist who flips a bird at you because you can’t quite yet change into second gear so you need to rev the engine.

      2. “Share the road” is a two-way street. Cyclists who ride down the middle of the road, oblivious to the cars stacking up behind them, drive me nuts. Just as bad are the cyclists who go from the middle of the road to one foot off the middle of the road, as if that’s some realistic concession. Just grinds my gears. And I’m a cyclist. Is common sense and common decency so dadgum difficult to understand???

      3. @Rob, yes there are bad cyclist. I once had to leave the road on the far lane while passing because one swerved out of “his” lane towards me, I ended up on the shoulder to avoid him. I would certainly never say I wish he was splatted, as others in the comments here have said of cyclists.

        BUT, all cyclists end up tail-gated. All cyclists end up passed by freaking maniacs who speed by while rev’ing their engines less than 6″ away from their bike.

        YOU have a responsibility to pass ONLY when safe and reasonable REGARDLESS of what the posted speed limit is. Like it or not its lawful for them to be on the road and to obey the law YOU MUST only pass when it is safe. Just like with any other vehicle. Would you get 3′ behind a combine on the highway??? Drivers do that all the time to bikes.

        *(I mostly ride motorbikes, but douches tailgate us too sometimes, and to the same end if something goes wrong).

    1. Hmm, we seem to be drifting into OT here but if I’m in the lane there’s a reason. Too many drivers are of the opinion that everything should get out of there right of way (do you see a fault with that last part?).

      And yes, I’ve had words with my own riders for not keeping single file when riding on the roadways. You are correct it does go both ways.

    2. or even better if there’s a side walk USE IT. Thats what its there for bike, and people walking, especially when its a nice big 10-15 feet sidewalk/bike path.

      Now if there isn’t one i am fine with them using the road so long as they don’t ride in the middle, but way too many will block a lane, where a car can’t go around them when there a sidewalk less then 5 feet to their right

      1. The sidewalk is for (stay with me on this…): walking.

        It’s in the word! It’s not the sidebikepath or the sidescootertrail!

        I’d like to meet the Derpington who decided to tell people it was OK to ride your bike on the sidewalk.

        Unless you are a small child, stay off the sidewalk.

        1. So-called ‘sidewalks’ are publicly owned, privately controlled off-street vehicular storage places. Anyone attempting to walk or bicycle on a ‘sidewalk’ is risking damage to precious motor vehicles.

      2. I don’t know what the laws are where you are from, but the sidewalk is absolutely NOT for cyclists. Where I live, it is illegal to ride on the sidewalk for that reason. The sidewalk is also the MOST dangerous place to ride a bike, statistically speaking. Cyclists are legally considered vehicles pretty much everywhere in the US, so sorry, learn to share the road. Back before cars were the predominant form of transportation, people on horses and bicycles didn’t want to share with cars because they viewed them as highly dangerous…

  3. Assume the ultrasonic sensor detects a car at the max distance of 6.45m, and the mildly increased flash rate *instantly* gains the attention of a driver who was previously unaware of you. Assume also that the driver has a response time of one second before they either slam on the brakes or swerve; which may be overly generous since if they’re just now noticing you, they weren’t very alert to begin with. A little simple math will tell you that if they’re going a mere 15mph or greater, by the time they take action, THEY WILL HAVE ALREADY HIT YOU.

    The use of an ultrasonic sensor here is a liability, not an improvement. When on a bicycle, you want people to be aware of your presence as early as possible; so the tail light should be flashing its arse off, full intensity, all the time.

    1. +1

      This type of technology is pretty useless. Given how few people actually get killed on bikes every year, this seems a bit paranoid to worry about…

      After riding about 10,000 miles in two and half years I have only had one accident… And that was caused by one of those ridiculous bicycling clubs who like to think they are racing the Tour De France every weekend…

      1. In the US (A population of about 350,000,000 we average between 700-800 cyclist deaths per year…

        And of those a significant number are children, who really shouldn’t be riding in traffic and the vast majority of the remainder involve accidents caused by alcohol…an number of which is the cyclist imbibing the alcohol…

        In short, cycling is actually pretty safe, and In my area most of the cycling accidents are cause by the TDF wannabe’s crossing wheels in their weekend pelatons…

      2. Maybe where ya’ll are from is like that, but here in Tampa, FL, that’s absolutely not the case. What you all apparently fail to realize is that if you make a little mistake while driving a car, it’ll probably only cause your car to get a little scratched or dented, whereas the cyclist gets seriously injured/killed, almost every time. It is ridiculous to say “Well it doesn’t even happen that often!” when the results are often so bad.

  4. I am not interested in hitting a bicyclist. However, as long as they insist on sharing the road with cars during rush hour (while riding into the morning sun), this is a distinct possibility, and not something that myself (or another car driver) may have control over.

    Bug splat.

      1. Pretty dickish thing to say to a non-biker.

        Never trust guys in spandex who bring bikes to a carfight and then hate everyone who doesnt get out of THEIR way.

    1. So you don’t have control over whether you drive into something… because of the lighting conditions?
      If you can’t see what you’re driving into, there’s a whole other problem here.
      Cyclists need to stay responsible for how they ride, but drivers need to understand that the road does not solely belong to them.

      Just a thought: if people are riding their bicycles during rush hour, it’s probably for the same reason YOU’RE in the CAR at rush hour. It’s not like they’re doing it to put you out.

    2. Go drink some drano douchebag

      You have not bloody right to run other vehicles off the road just because you are bigger.

      “Insist on sharing the road”???
      Do you even have a valid drivers license?
      How could you be so bloody stupid?

    3. If you can’t see a large metal object with 70 kilos of meat on it, moving and sticking almost 2 meters up from the ground, how will you avoid things like pot holes?

      Also, how do you see the center line markings on the road?

      If you seriously cannot see a cyclist, you are either driving waaaay too fast, or you are vision impaired enough you should not be driving at all.

      1. I tend to disagree. There are times in the morning and evening, while on a East-West running road, for at least a couple of weeks every year, that it is very difficult to see smaller pickups, much less smaller cars or even bicycles. This condition is made MUCH worse by frost, condensation, or a slight haze on the windshield.
        The worst part of this is that the windshield will not appear to be dangerous until the windshield is at the proper angle to the sun. It can change from clear to blinding in the amount of time it takes to crest a hill, come around a curve, or just come out of the shade.

      2. Absolutely. I have to say it isn’t technically always someone’s fault for not seeing a cyclist as they tend to be usually unspectacular (not wearing all neon clothing) and are moving at a very unusual speed (15mph or so) which most drivers aren’t used to. It is very easy to see a pothole in comparison, because a pothole isn’t moving. But still, if you don’t see someone and hit them, it is still your fault, EVEN if the odds are against you seeing them. Now that doesn’t mean you are a douchebag because the sun hit your windshield at just the right angle, but you are still liable since you are driving the car.

  5. Keep flashing lights off, unless it is an emergency. I had a cyclist behind me one of those rare times for me in a cage, at night. Being trailed by flashing lights, ought to be illegal. Get and wear a rearview mirror. Helmets won’t let you see behind. Flash your brake light 3 times. What no brake light, get hacking!
    Those puck sized blinking led’s form a decade ago are bad enough brighter has to stop blinking. By law.

  6. This is a great idea and could be a bit seller if produced commercially.
    I bike commute at night and have had two friends who also do get struck from behind by cars and badly injured. Both by drunk drivers.
    The addition of a missile launcher would also be a nice touch.

    1. A better hack to deal with getting hit by a drunk driver at night is a night vision camera that records to a remote server or hardened drive on the bike. They’re drunk. Flashing leds will not do squat to prevent them from hitting you, especially if they only react at the sensor range. A camera would at least help catch and prosecute the driver.

  7. I like big bright strobes. And really, you can use a 555 and HV circuit across a strobe tube.

    And if you really want to integrate the Arduino, have it judge the distance and start tossing caltrops behind you if vehicles get too close. They’ll learn mighty quickly not to tailgate a bicycle. Yes it’s a little malicious but hey, we own the road too.

  8. As a cyclist (and occasional driver) I DETEST flashing bike lights.

    Driving on a completely unlit road I almost pulled out and ran over some dumbass cyclist because his (only) front light was flashing. Due to the sharp angle of the junction I could only see him (well, just his light) in a traffic mirror (one of those curved ones) and it looked like a roadworks hazard light in the distance, it wasn’t until the last second I could tell it was actually moving so didn’t pull out and run him over.

    A moving blinking lights can be very difficult to judge how far away, what speed and what direction it is travelling in, especially in darkness when there are no point of reference and when you can’t see the actual bike+rider.

    Unfortunately they are road legal in the UK, I wish they weren’t.

  9. I have biked a lot of miles, all my life and never seen a use for such a product. I try to stay off the busy roads and use my common sense to stay out of confrontations with cars. It’s pretty obvious when a car is on your tail, MOVE OVER and let him by!

    There is probably a quiet road just 30 feet away from the busy one you are riding on, which provides a much more enjoyable biking experience and nobody riding your tail.

    I swear half the cyclists out there are just looking for a confrontation these days. I am both a car and a bike commuter so I see both sides… and I am sick of “critical massers” giving the ordinary bike commuter a bad image. Take off the spandex and ride like a man. This is a commute not a race, so don’t act like such a knob.

    Cowardly cyclists always start shit with motorists and then ride off knowing there is nothing they can do other than hit them (which is excessive and won’t be done… so – no consequences for bad behaviour) If you want to fight, I won’t use my truck as a weapon, lets both pull over and we can have it out with fists on the side of the road!

      1. The point the previous poster made still stands, despite your hysteria. Given recent news this post would be like claiming zombies are real because a few nut cases have started eating people.

        Only 700-800 cyclists are killed each year in the US. Approcimately 40% of those involved alcohol on the part of the driver or the cyclist… Something that no safety equipment would prevent..

        It just isn’t a major concern. But recless cyclists cause much of their own problems.

    1. Why the bloody hell should I have to run OFF of a road that I HAVE HELPED PAY FOR because some douchebag like you is tailgating me.
      Maybe I’ll get a flat driving through the broken beer bottles that other douchebags have thrown to the shoulder.
      Did you even think of that?

      Dispshits like you truly amaze me.
      No one tailgates construction vehicles, No one tailgates farm trucks.
      No one passes those like a self-rightious turdfondler.

      But end up with a small vehicle moving slow and people like you turn into homicidal jerks.

      1. Folks tailgate construction vehicles and farm trucks all of the time…

        Get over yourself, cyclists like those other two vehicles you mention are simply annoying obstacles for the vast majority… Cyclists need to get over themselves… most of the time they cause the problems they perceive…

      2. @WA, may you or yours have it in with some larger vehicle piloted be a self-imprtant scumstain like yourself.

        Is it really that big a bloody (and YES it can get REALLY bloody) a deal that YOU are SOOOOOO VERY inconvenienced by taking 15 seconds out of your day to pass someone safely? It is YOUR responsibility to pass them safely, even if they’ve pissed you off by their mere presence on YOUR roads…

        No, instead wankstains like yourself try to intimidate others off of the roads, roads they have every lawful right to be on, by intimidating them with the size of their vehicles and the threat of a potentially lethal collision. Thats called AGGRAVATED ASSAULT in any other setting. If you tailgate anything you’re a douche, YOU get over your worthless self or kindly wrap your neck around a tree.

      3. Hold on there slugger. Maybe I’m the ignorant here, but I thought that road were designed primarily for MOTOR VEHICLES and not a ~150 lbs ego bag on a 2 wheeled thing. I do know that some road have cycling lanes and that motor vehicle drivers have a large expectation of being responsible on the road, but that doesn’t mean that cyclist don’t need to be uptight you know what’s on when it comes to who ‘owns’ the road.

        Is it just me, or is anyone else perplexed why some cyclists (or runners in the road when a useable sidewalk is only feet away) insist on acting like they own the road? I’m no medical professional and no physicist, but motor vehicles vs. person (with or with a bike) is a loosing battle for the person. Based on that and how you’ve drivers act irresponsibly all to often… do you really trust the random driver to not to hit you 100% the time?

      4. @cornelius

        Are you suggesting it is acceptable for you to use your motor vehicle to intimidate others?

        Perhaps you don’t realize that many of our roads predate the now common automobile. It used to be if a car hit a bicycle the driver went to prison. Now they “just let the insurance take care of it”.

        So no- most emphatically NO, roads are not only for cars. It is lawful for the bike to be there – with a few exceptions then hey, I expect them to obey the law too. But this thread is about douchy drivers, not douchy riders- who fortunately mostly endanger themselves when blowing through a stop sign (see it a couple times a year) or riding three abreast (seen once in my life, but it was this year).

        It is unlawful for you to pass a bike in a dangerous fashion. Even if they are going 15 in a 25, or like me on my little motorbike I’m doing 45 in a 60. Even if, get this, even if you are running late for work, you may not tailgate another vehicle, you may not rev your engine with the intention of intimidating them, you may not swerve violently towards them, you may not throw your beer can out the window at them, etc etc, etc. In many states if you come within 3 feet of them YOU ARE VIOLATING THE LAW. In any state tailgating anyone is violating the law. Yet douchebags routinely swerve violently towards me, sometimes coming just inches from my mirror- just because I’m not going fast enough and they wish to bully me. And to be clear I’m talking about rural roads with almost no traffic… some people, like you and others in this thread, simply have no bloody sense that you might be expected to behave safely towards others when you’re in public.

      5. @thebes42

        You seem to have a reading comprehension problem…

        You made a claim, that I refuted. You said, cars don’t tailgate farm tractors etc.. That simply isn’t true.

        As to how I should behave while driving… That isn’t something I do very often, since I run almost all my errands on bike.

        I have a problem with a very specific kind of cyclist. Those weekend warriors, who like dream they are riding in the Tour De France every weekend by riding in pelatons…

        I was put in the hospital, while riding a bike, by such a group, when they passed in front of me and hit my front wheel…

        Such groups, riding in the streets, are illegal in every jurisdiction I am aware of. And if you want to know why look up laws relating to following at a safe distance. Since those group rides are designed to make use of “drafting” they are illegal on that principal alone, much less the fact they never obey other traffic regs…

  10. I made something just like this 6 months ago after my friend went biking with me and I was sick of lots of cars driving too close. My heaps in my headphones when a car is 50ft away and strobes slightly quicker as a car passes. But I have 3x3w taillights.

  11. or the u.s. could put in separate bike paths and better infrastructure like those biking meccas in the netherlands. I am also the king of the ants and made of figs.

  12. Kansas require tail lights to be visible from a distance of 500′, I’d imagine most States have similar regulations. With modern LED bicycles probably could meet that standard or better. INMO the use 6″ square brake/ tail light assembly a motorcycle assembly should be reasonable compromise. Although I understand there will be car drivers that would still pitch a bitch about that.

  13. Rats… I thought bikers were worth 50 points. Wasn’t it George Carlin that use to talk about getting right up to the cyclers pedals. Too funny!
    Honestly though, this device would make them more annoying than they already are. I’ve rarely come upon a cycler that totally follows the rules of the road, yet they gripe at auto drivers. As the saying goes, its a two-way street.

      1. You know the roads were built for cars to use right? Dont ride down the damn middle of the road, if you are then you better damn well do the speed limit. I followed 3 bikes one time…riding side by side down the middle of the road at least 10mph under the speed limit. This was in town and there was no way around them. And you wonder why no one likes bicyclists.

      2. (Note, I am both a motorist and a cyclist)

        You know the roads were built for cars to use right?

        No, roads were build for all vehicles (and that includes carriages, bicycles, bulldozers, etc.). If a huge truck carrying heavy machinery was in front of you, going at 10mph, I don’t think you’d try to force it off the road…

        Don’t ride down the damn middle of the road, if you are then you better damn well do the speed limit.

        Wrong again. You understand it’s an upper limit, right? You are not obliged to ride at that speed. There are roads with minimum speed limits (e.g., motorways), and of course there you have to follow the minimum speed.

        Sometimes, driving in the middle of the road is the safe thing to do. If motorists could be trusted to follow the rules (like stopping at Stop signs, checking the road before a right turn, etc.) then we could drive closer to the right side of the road.

        That said, annoying motorists “just because we can”, is of course stupid.

      3. I really don’t know where all these motorists are seeing bikers in the ‘middle of the road’. i think maybe, MAYBE, once in a while, someone has to move out of the way of something blocking the bike lane or road and has to come out to the ‘middle of the road’ for 2 seconds and it pisses off all these motorists so greatly.

        I live in Chicago, a place with a ton of bike lanes on shared streets and I don’t really see cyclists in ‘the middle of the road’, blocking traffic, being annoying etc. They are in the bike lane, out of the way of cars.

        What I do see though, is motorists going the wrong way down one-way streets, hooking right turns from the left lane, reversing down the highway because they started to take the wrong ramp, taking a turn and ‘gliding’ into the farthest lane instead of the closest one (why people do this, i’ll never know, too lazy to turn the steering wheel an extra turn I guess), driving in the clearly designated bike lane…and people wonder why motorists are so maligned?

        Its a two-way street, Herpadurpington.

        I love how any time there is a bike safety post on the internet, all the road-ragers come out and post like hardasses.

      4. @1wayOut

        It’s called a speed “limit” not a speed “target” you twonk.

        Oh I’m sorry, I forgot you’re one of those who believe that driving on the roads is actually a race not a means to get from A to B.

      5. ACTUALLY… I’ve been there when a friend got pulled over and got a ticket for going to slow, so its not just a max speed either! Maybe you should check with your local authorities before you comment about that again.

        To the others… Cyclists around my area ride 3 wide and do not move over for traffic, then they have the nerve to get pissed when you have to pass them in a hurry. They do not signal turns properly, nor stop at stop signs — so how about following the rules of the road cyclists? The roads have shoulders for a reason, if the road you are attempting to ride on does not have a shoulder you should consider an alternate route, or drive in the dirt. Check your local law book for this… If you cant keep up with traffic and as a result may cause an accident then pull over to the shoulder — that goes for cars, motorcycles, truck, bikes, or donkeys.

        Like someone else said, its not the tour de france, when a vehicle is attempting to pass don’t ride 2 or 3 wide…. Maybe the spandex is to tight and it cuts off circulation and causes poor decision making skills??

      6. There is a road out in the country that the bikers love to ride… and the local cop loves to hang out at. He will pull them over because they run a stop sign. A friend of mine got pulled over for not stopping not only got a ticket for not stopping, but also for not having his license with him. Love it!

  14. My choice is a 1 Watt RED blinker. If I am not causing them pain by looking at me, It’s not bright enough.

    And if they are not annoyed by the red blinker for the past 3 miles as they were approaching me, IT’s not bright enough.

  15. Cars are a recent arrival on the roads and have been there for a short period of time relative to the existence of roads. The idea that cars have precedence over people, bikes, horses, etc. only dates back to the mid to late 20’s when the major car companies began to campaign so they could increase their market.

    In some cities cyclists are encouraged to ride down the middle of the road in order to keep a car from attempting to pass where it would be unsafe. Before getting excited about the uppity cyclist check your local regulations.

    Bike lanes in the city chew up either parking, an existing lane that was for cars, or an entire road. It might be better to share what is there.

  16. About as useful as a £1 “IF YOU CAN READ THIS, YOU ARE TOO CLOSE” bumper sticker. Excepts it costs a lot more. And it eats batteries. Only thing it’s got in common with the sticker is its effectiveness: none. If people care, they won’t tailgate you, and if they don’t, they’ll flip a bird at your gizmo, or may even make it worse on purpose.

  17. Bicycles are allowed to take the lane in practically every jurisdiction on earth. dont expect us to get off the road just because you are impatient, and don’t pass dangerously close to us (dangerous is subjective, but 18 inches is a decent bare minimum) and quit thinking its such great fun to right hook us.

    contrary to your beliefs, we are people too, and what might save you 30 seconds could cost us 30 years.

  18. Both a car and a bike on average transport about one person per vehicle. A car always takes up a lane space; a bike seldom takes up one. Bikes can also take side streets, and safely cut across parking lots to avoid intersections. These characteristics make bikes much more efficient users of road space.
    Thus, bikes improve traffic flow; they don’t impede it. If in some major world cities (eg: Paris, Beijing, New Delhi, Oslo) bikes were replaced by cars, pavement wouldn’t see daylight and traffic would come to a standstill.
    The cars are the piggy problem. The bikes are (part of) the civilized solution. `~- Nehmo

  19. So much hate. Expected whenever bikes on the road comes up. I am all about hating on cyclists for various bad behavior from having a background as a professional driver. At the same time it is just as bad to tailgate regardless of speed or vehicle type.

    I just don’t have the heart to go either way. Golden rule applies. Don’t be a dick and all is fine.

  20. My country drivers hates cyclist, because a toyota cost 1500times a normal mountain bike so they will definitely run you off the road just because they can. But again I dont see cyclist on the road anymore hmmmm

  21. I’m also working on a device to alert both rider and driver when they are in close contact to each other. What made you choose for a Sonar sensor rather than a Passive InfraRed sensor? Also, I believe more in illuminating, or actually personifying the rider than scaring of the driver. If the driver wanted to be cautious, it would have recognized you in the first place.

      1. Then how did you manage to exclude any cars that are parked next to the road and the fact that the bike is riding itself? As I’m experiencing some difficulties in accomplishing that

  22. Not to hate on cyclists but I have found where i live (near Perth in West Australia) there are large groups of cyclists who have a very bad habit of riding in packs and completely ignoring the road rules, they travel well below the 70kph speed limit ride 3 or 4 abreast across lanes and ignore traffic lights and stop signs, this speaks badly for all cyclists especially since there are easily accessible bike paths right next to the road.

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