Bikes don’t stop faster than cars. Plenty of cars approach 1G of deceleration. At .3Gs I’m going over the handlebars of a bike.

Furthermore, in NYC, half of serious pedestrian injuries are caused by bikes, meaning a cyclist is about 200 times more likely to seriously injure a pedestrian than a driver.

I am all for bikes, but let’s not be delusional about the safety issues or basic physics of how poorly they brake.

>> Furthermore, in NYC, half of serious pedestrian injuries are caused by bike

I would be interested to see that citation.

I would also note that very very few people have ever been killed by a bicycle, which cannot be said for cars.

8 over the past 15 years, vs 2300 killed by cars: https://www1.nyc.gov/html/dot/downloads/pdf/nycdot-pedestria...

The BYC DOT publishes stats every year that refute this completely. About 30x as many pedesttrians are hurt by cars vs bicycles, and 100x as many killed. You would expect that same ratio to stand up to whatever the GP means by "serious injuries"

>> in NYC, half of serious pedestrian injuries are caused by bikes, meaning a cyclist is about 200 times more likely to seriously injure a pedestrian than a driver.

This absolutely false, but nice try.

2017 city wide stats:

Bicycles: 315 accidents involving pedestrians with 1 fatality. Motor Vehicles: 10,561 and 106 pedestrian fatalities. Not to mention 4,397 bicycle injuries and 24 fatalities.

http://www.nyc.gov/html/dot/downloads/pdf/bicycle-crash-data...

Not OC, It would be great if you could normalize the data for number of cars/bikes and for Km/miles done (I do not see this data in your link). Because I am wondering if maybe there are fewer bikes then cars so the numbers comparison will be unfair.

I am not against bikes, cities need better infrastructures, I only needed to drive once on a busy city and I said that I never do it again.

On the other hand, car infrastructure tends to be better separated from people walking compared to bike infrastructure.

A longer distance car drive may happen on a highway fully separated from pedestrians, while cyclists are almost always on bike lanes right next to sidewalks or trails/paths basically shared with pedestrians.

Car infrastructure in most places probably has had 1000x as much money pumped into it as bike infrastructure. If bikes had even 10% of that, you could have luxury, hyper-safe bike paths anywhere and everywhere.

I know, if the numbers look bad for bikes in cities with bad infrastructures and better in cities with good infrastructures after normalization then you can show that investment prevents deaths. Sometimes pedestrians are at fault too so everyone would be safer if bikes can be separated from pedestrians and if data confirms this force a speed limit for bikes on certain sections.

If you're going over the handlebars of a bike at .3Gs, I think you might be using your bike incorrectly. I'm personally limited as far as braking mainly by my tires slipping or, on downhills, by stoppies. All of which happen at much more than 1G.

Motorcycles can also generally brake at 1G, again limited by the presence of an ABS system, so it's not a physics question, it's that either you have bad brakes or you do not know how to brake on a bike. Even only using the rear wheel should allow you significantly more than .3G

I did some measuring and thinking when I returned my bike to the bike room. I looked up some stuff, and .5g is where one typically goes over the handlebars. .3g is typical stopping speed for an average rider. Elite riders can achieve .7g by moving their butt way behind and below the seat. The front tire friction limit is around .8g with good dry conditions. My bike is way too small and I have the seat post about 1cm into the tube, and I’m also a bit top heavy. The wiki page on bike physics says rear wheel only braking gets about .25g.

https://en.m.wikipedia.org/wiki/Bicycle_and_motorcycle_dynam...

I measured my mountain bike, and the seat is 41” high, and 35” behind the front contact patch. This is terrible for braking, though not entirely out of line with some of the fancy road bikes in the bike room. I should probably get a different bike, as I am quite sure I go over the handle bars at about .3g rather than the more normal .5g.

At any rate, I am not sure how one learns limit braking on a bike. Modern cars the computer does it for you if you just stomp the pedal and some cars even do it preemptively with collision avoidance.

Apply both brakes. When the rear wheel starts to skid, you are near the limit of your braking ability with the front brake.

https://www.sheldonbrown.com/brakturn.html#frontuse

It's really quite simple. And you learn it with cursory research about braking on bicycles. Really this ought to be taught in schools.

One learns to avoid locking up the brakes by feel and experience. ABS is not necessary, though it is more reliable. For an extreme example, Formula 1 drivers or MotoGP drivers do not use ABS, and yet are able to brake at the very edge of possibility.

Indeed, it is actually possible to brake ever so slightly more efficiently without ABS than with ABS using very slight wheel slip, and smoother braking allows for weight pre-loading going into a turn.

https://www.nathanarose.com/blog/2017/10/4/braking-capabilit...

According to this study, braking using both wheels on modern motorcycles (And, by extension, modern bicycles as both have in the past decade standardized braking systems that operate at the limit of grip) achieved .75G +- .15G. This is without ABS, and the limit using perfect braking at higher speeds yielded deceleration rates greater than 1G.

If the average, skilled rider is able to achieve .7G on modern bikes, this is not at all worse than cars where the average driver is assumed to brake at .4G. According to https://nacto.org/docs/usdg/vehicle_stopping_distance_and_ti... , a moderately skilled driver is assumed to be able to brake at about .5-.6G. This compares favorably.

As for braking technique, it is about extracting as much braking force as possible from the rear tire, then attempting to lower one's center of gravity by leaning down and backwards. An absolutely crucial difference is that in a car, braking is very detrimental to turning, causing over-steer. This is not so on a bicycle or motorcycle, which contributes furthermore to safety, as most accidents are avoided via steering, then steering and braking, and then only braking.

According to this, braking forces of up to 0.83G are possible on a normal bicycle, without suspension nor special positioning: http://www.industrializedcyclist.com/braking-pitchover.pdf