That said, I don't run lights, and am just as baffled how some cyclists will barrel through a red light at intersections without even slowing down...
I'm cycling for a bit of outside time and exercise in my day. If I have to stop at a light, then fine, it's a bit of extra exercise and outside time.
I'm not there for the excitement of some kind of death race with stressed out drivers.
Bonus points, use a bike with internal geared hub and shift down after you stop.
With that mentality, one can see why so many cyclists disregard safety around intersections and stop signs - mentally, the feeling of doing an unsafe thing doesn't suck as much as the feeling of "losing" (even if it's just an emotion not grounded in any logic or reason). Regardless of whether it's logical or not, there's also this: https://en.wikipedia.org/wiki/Idaho_stop
I'm using the value of Cd * A from here (0.6 m^3): https://www.sheldonbrown.com/rinard/aero/formulas.html
That page also indicates that the vast majority of the energy expenditures on a bike are due to drag.
The fraction of energy needed to get up to speed divided by the energy expended due to drag works out to: (mbike + mhuman) / (Lblock * rho * Cd * A) where mbike is the mass of the bike, mhuman is the mass of the human, Lblock is the length between stops, rho is the mass density of the air, Cd is the drag coefficient, and A is the projected area. I can post the derivation if anyone is interested.
Assuming an 8 kg bike, 90 kg human, 200 m between stops, and an air density of 1.2 kg/m^3, stopping adds 68% more energy.
This is dependent on the weight. If I crunch the numbers for my own weight, stopping adds about 56% more energy.
So, this is higher than I expected, but I don't think it's so much higher that it justifies running red lights.
I think this calculation is basically right, but might be a bit worse for the average commuting cyclist. Many commuting bikes are heavy and badly maintained, so rolling resistance is likely to be a larger factor. Also at the low (max ~25km/h) speed of many commuting cyclist rolling resistance is almost as significant as air resistance. [1] indicates that up to around 17km/h it is as big a factor as drag, but that is on a well maintained bike.
Anyway, 400W to avoid getting creamed by a car seems cheap to me.
Eat a Clif bar; stop at red lights.
Goddamnit.
An engineering student designed something like that, using a flywheel: https://www.treehugger.com/bikes/engineering-student-builds-...
But if you want something commercially available, you have to get an e-bike with that feature, and those models seem quite pricey.
The flywheel thing is exactly it, except I think it would be safer and lighter to use compressed air, also stores longer than a flywheel.
With something like that you'd eliminate most of the work penalty for brief stops.
Edit: I will admit that I rarely come to a complete stop at a stop sign. It definitely is a considerable inconvenience to get back up to speed, but a lot of safety precautions are inconvenient.
That's back of the napkin. Bone apple tea!
I don't see a problem with bikes running red lights. It's not that much different from crossing any other intersection where cross traffic isn't stopping. Generally I avoid traffic signals on my commute, but there is one place on my commute where I almost always run the signal. In this particular intersection, it's less dangerous crossing by myself against the signal than crossing with the signal next to a bunch of cars trying to pass me.
The fundamental problem is in most places traffic controls are designed around the needs (and safety) of people in cars. Bikes and pedestrians are usually an afterthought.
Cyclists who speed towards or through an intersection when they can't see what might come into conflict with their path are as stupid as drivers who run reds.
My understanding is that taking the lane at an intersection is often recommended, and some cities create special "bike box" infrastructure to encourage cyclists to do that, though few do.
I wouldn't recommend blocking the crosswalk, but my experience getting in a long line of cars is good.
I sat in a corner desk right on top of a major central business district intersection. Cars never ran the light, it's too busy and complex. Cyclists did reckless, stupid shit all of the time, running lights, cutting across the diagonal on the wrong side of the road, etc.
From my POV, drivers are more predictably dumb, and dangerous when they perceive low risk, for example, they run red lights in a low traffic neighborhood and are awful about a number of things. Cyclists are less consistent and perceive risk differently. Younger people who perceive themselves as invincible in particular.
End of the day, we should have better dedicated infrastructure for bicycles and other things.
I have never seen a cyclist in the UK run a red light at a complex intersection (often only running the 'quiet' side of a T-junction, or an empty junction with a 20MPH speed limit and no cars in sight). Also worth noting is that the roads in UK cities are much narrower, I would guess 40-60, and often have less lanes and often have a bike lane of some sort.
In the US (California) I have seen all the crazy stuff. People running red through traffic, people doing a U-Turn, people going the wrong way, people crossing to go the wrong way, people blowing through a red light whilst on their phone.
However for cars, the UK has more stop lights that are for cars giving way to pedestrians, i.e. there is no junction. I have sometimes seen cars run a red on these when they don't notice/care. However in the US the red lights are at junctions, and are therefore more dangerous for cars (getting T-boned) I have however seen more people run these still.
I can understand the spirit of the law but in practice cyclists interpret this as "it's ok to red lights if I don't see any oncoming traffic". This turns out to be extremely dangerous because a situation can change in seconds especially when high velocity metal objects are concerned. Blindspots are always a problem.
This issue has salience with me because a cyclist who ran a red light at the intersection near my house got hit by a car that was following the rules of the road. There was a dramatic video on Youtube of the cyclist getting hit and flying off his bike. I don't know if he survived.
As both a cyclist and a driver, I can't emphasize enough: cyclists need to follow the rules of the road. It is not ok to run red lights.
[1] https://www.cyberdriveillinois.com/publications/pdf_publicat...
If you don't think it was that close, consider that the wide angle lens on my helmet camera makes the incident appear farther away than it actually was. Out of all the incidents I've had in the past year, this was one of the worst in terms of potential for serious injury. If I was a foot or two closer, there would have been a collision.
The main thing I learned from this incident was to not focus too much on people turning from my right. That's where my attention was approaching the intersection. I need to also consider the possibility that someone will run the light.
I don't know how bad it would have been if he hit you. A broken bone and a lot of scraped off skin. For some people that's a risk worth taking. Does that mean falling behind in work, insane medical bills and stress on the family? I don't know if cycling is worth it for everybody. It's not my place to say any of those guesses about what it means to you in real life. I'm curious what the stressors are for cyclists. Being in a car crash at least gives you the peace of mind that in a reasonable accident the car will take all the damage and you can walk away and get a rental.
All that being said: DO YOU GUYS ACTUALLY WANT TO DIE? I’ve never seen any group of people ignore traffic laws and common sense more than cyclists. They consistently ignore signals and four way stops and ride on two lane highways with high speed limits, no shoulders, and blind curves.
Yes the roads need to be shared (and personally I think cars should be banned before things like bicycles and scooters) but dang people need to behave.
Straight up running red lights or stop signs does seem like it is overrepresented by cyclists, but I really don't they they're overrepresented for generic 'breaking the law'.
Cyclists and to a lesser extent scooters throw a wrench into things because we as a society haven't yet had time to reach a consensus on what the norms for these classes of traffic are and how they should behave so people fall back to the law.
This is why people get all "but the law" when cyclists run reds but don't care when cars roll stops or speed (under appropriate circumstances). We've established that the latter is ok but haven't yet reached a consensus on if the former is to be expected as part of normal traffic flow.
To solve this problem, just get off the seat when you stop.
many states have a "dead red"[1] law for when lights are not operational. which permits the cyclist to proceed with caution after stopping.
[1] https://en.wikipedia.org/wiki/Traffic_light#%22Dead_Red%22_l...
There are quite a few places in my city, where I have no idea what the legal way to get from one side of a large road to the other. Sure you can always act like either a car or a pedestrian, but that is either dangerous or slow. For example, I find it quite unfair, that many left turns require me to either ride between cars or stop twice.
Some bike paths just look like the planners reserved space at the roadsides and simply skipped coming up with a solution at the intersection. And that is frankly disappointing.
cyclists are more likely to run red lights than scooter riders
In my experience, the vast majority of the time cyclists run red lights, they check both directions before going and there are not conflicts. The examples shown in the article are fairly rare.
Plus, the danger from a cyclist running a red light is mostly to the cyclist, while the danger to a driver speeding is to everyone nearby on the road.
Add on top of that the fact that there are many more drivers on the road than cyclists. The net effect is that speeding is a much bigger safety problem in total than cyclists running red lights.
(Note that I'm not endorsing running red lights.)
It's also dangerous to pedestrians. I see cyclists run red lights with pedestrians in the crosswalk almost every day, and many of them seem to assume that people will stop walking and yield to them. If somebody doesn't notice the cyclist then this can easily lead to a collision.
I've never seen an accident arise from running a red light.
Which isn't to say that I think running a red light is "safe" but I think the context in which one runs a red light is probably a bigger factor than blanket denunciations imply.
In America, running a red light usually means something like "while driving a 4,000 pound car at 40 miles per hour [6.4 million mv^2], the driver blows through the red light due to complete unawareness of the signal."
Whereas where I live it is more like "a guy on a scooter (360 pounds net), slows down (somewhat), sees a gap in the traffic and zips through at 15-18mph." [116,000 mv^2; the car is 55x worse]
Over the years I've been amazed by the arguments other cyclists have used to justify running red lights. The "physics" argument mentioned in the article isn't convincing to me, because a cyclist's kinetic energy is lost relatively quickly to drag and friction anyway. Stop pedaling. How long will you coast? Probably not very long (i.e., over 100 meters) unless you're going downhill. Seems to me that cycling requires constant energy input and stop lights and signs aren't likely to contribute much to energy expenditures. (Maybe I should do the math...) Edit: I did the math here and the energy from stopping was higher than I expected: https://news.ycombinator.com/item?id=22257938
I think the time saved from running reds is much lower than most red light running cyclists believe, because anecdotally I observed that red light running cyclists tend to go fairly slow. I can recall keeping up with or catching cyclists who run red lights despite never running them myself.
I think cyclists as a whole need to stop running red lights. Yes, there's a double standard here, as most drivers seem okay with speeding if they're doing it, but can't tolerate rule-breaking from cyclists. But we shouldn't give drivers excuses.