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Comment by enoch_r | Hacker News Reader

The problem with this theory is that the speed limit on that road is 40. If she was traveling well under the speed limit but did not have time to stop for a turning car, then it seems to me that either a) the intersection is designed such that a vehicle traveling the speed limit will be unable to stop before colliding with a turning vehicle, or b) the driver turned after the bicyclist had turned the corner. Or, of course, a combination of the two--it may well be that the intersection is fairly dangerous for drivers as well (and some commenters have talked about previous accidents at the same intersection).

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It seems entirely possible to me that the van driver was actually taking the corner "too slow" (though I'd be taking it slow too based on blindness of the turn if I wasn't used to that area) resulting in a situation where there was an obstacle in the bicyclist's path that was difficult to avoid at the speed that she was travelling.

And yes, this would also mean that turn would be dangerous for other cars as well in this situation, but modern cars actually have a much easier time of safely breaking while curving and going downhill than a person on a bicycle would (way easier to crash the bike or slide it out) and the car would be further out to the left of the lane than a bike would.

Of course, this is all speculation, and this is a horrible tragedy no matter how it happened, but I think some people are calling for the van driver's head way too early on this. And I say that as someone who does quite a lot of biking both mountain biking and on the roads.

I agree pretty much entirely. It's entirely possible that no one was at fault, or even that the bicyclist was, say, looking down and didn't notice the van until too late. And please don't think I'm "calling for the van driver's head." I have made so many mistakes while driving, riding a motorcycle, and bicycling that could easily have led to the death of me or other people if the conditions lined up right. Dappled sunlight through the trees, relatively high speeds for a bicycle, a sharp corner, and a tiny side-street are a really dangerous combination.

Yeah agreed. It is also possible the driver was at fault, I just think we don't have enough information to say what happened for sure.

Ultimately, I think most people would agree that regardless of where fault lies in this particular accident (which doesn't change the tragedy of it at all) this is a very dangerous intersection to have both bicyclists and drivers travelling at the current speed limit with such blind turns, curves and grade involved.

I kind of agree with you (see my edits), but it is harder to decelerate on a bike than in a car, especially going downhill - you run the risk of going over the handlebars.

In all fairness that depends a great deal on the skill of the rider too.

I'm going to show my lack of cycling knowledge here, but I really don't understand what you're saying. Why wouldn't one just use the rear break and set their body, like when one rides a bus and has to stand?

Well, the front brake has ~70% of the stopping power (both on bikes and cars), so while that will work (assuming you don't skid in the back), it won't be the fastest. You can get quite a bit of stopping out of your front brake without going over, you just have to be precise.

Even so, your center of gravity is much higher than in a car so you are not going to be able to brake as fast without flipping.

Your mass is far lower, though.

You can adjust your center of gravity on a bike.

It's still nowhere near as stable as a car with 4 wheels and all that metal close to the road.

You've got a lot more ability to shift your weight on a bike than on a car.

The only time my rear wheel has left the ground while braking is when I've tried to do it intentionally. And I've made plenty of hard stops in thousands of miles of riding.

You also have to keep in mind road bikes don't have disc brakes so precision is not part of road bike brakes. Those are most likely caliper brakes, which actually lock up fairly quickly when pressure is applied to the brakes.

I think a lot of higher end road bikes do have disc brakes these days. I'm not sure how prevalent or good they are though.

That isn't generally the case, partly because higher end road bikes are concerned with weight reduction, and disk brakes are substantially heavier.

Modern road bike brakes are plenty powerful enough with adequate modulation.

The real limiting factor on road bikes is traction.

Disc brakes on road bikes might give a distinctive advantage, even with greater weight. Disc brake rims need not have a braking surface and thus can be lighter having less angular momentum.

It might be easy to go into a skid and lose control. I guess it depends on road surface, and maybe it's not an issue for the pros, but I nearly got into an accident once trying to suddenly stop using rear brakes while going a bit downhill.

In addition to the other explanations about braking power, the reason why you have little breaking power is that most of your weight is over the front tire -- especially going downhill. Locking the back wheel up, means it just skids across the road.

Not really. While I'm sure you could grab the brakes hard enough to launch yourself over the bars, there is a LOT of braking power to be had before that point.

I ride close to 6000 miles/year, most road cycling, racing criteriums and road races. Going over the bars because I simply grabbed the front too hard isn't even the top-20 things I worry about.

I had something similar happen, while coming downhill a car popped out of no-where and instead of just breaking, i also turned sharply and flew over the handle bars, luckily on the good side! The way we react in a split second of panic is not the way expect we will usually react.

One question though, her IQ was 173? Einstein's was between 160-180.

Einstein appears never to have taken an IQ test. See

https://news.ycombinator.com/item?id=6415373

(posted earlier in this thread) for more about the late Amazon executive's IQ score.

How do people actually get to know their IQ? Are they so full of themselves that they go and get tested so they can know just how superior they are? Or is it something standard in some part of the world?

I think the point was to speak well of the dead: their acheivements, humanity and even their attributes. She was quite beautiful as well.

I got tested as part of an entrance exam to my elementary school.

You can usually estimate based on other standardized tests for people who haven't taken (or publicly disclosed) an IQ test. It's possible that the 173 figure is based on her CPA exam results or SAT scores.

School, typically. Had to do them at 9, 12, 17. I got dumber with each successive one.

> One question though, her IQ was 173? Einstein's was between 160-180.

It's not about how big it is. It's about how you use it.

What's your point?

This

Or as TBBT mentions, Sheldon has an IQ of ~180 but he didn't know you could call soup delivery (or something like that)

Or to make a simpler analogy: Being 6ft tall helps if you play volleyball (may be even a requirement), makes no difference if you play soccer.

IQ is just another meaningless metric. I'm supposedly 183, but I'm still a moronic cracked-out buffoon who struggles to remember what he ate for lunch.

On a hill? I was going too fast down a hill on a road cycle. Had a car behind me, and a very slightly raised manhole was ahead.

I braked, and went flying hard over the handlebars. I am not sure if I was going over before the manhole or not, but the hill radically changed how the brakes worked for me.

It depends on your technique. If you have the technique down it isn't difficult to rapidly decelerate on hills. It's mainly just a matter of bracing yourself, keeping your centre of gravity back and modulating the brake.

If you're not prepared for it and slam the front brake on your weight will shift forwards and you'll have lift off.

Riding trails for so long I sometimes take for granted the instinctual awareness of center of gravity without which its impossible to become even an intermediate mountain biker. Getting your weight back makes all the difference going down hill.

The bigger problem on a road bike are the skinny tires and twitchy handling make it very easy to fishtail and topple over when braking at speed.

I think the key here is "If you're not prepared..." in a high speed traffic accident you're very likely not to be prepared.

I was not there when that happened to you and I might be wrong but I cannot imagine that happening under normal circumstances. I used to race and during many thousand kilometers on the road I encountered many risky situations (including a car appearing out of nowhere if front of me while I was going down the hill on multiple occasions) and I am afraid of many things while I am on a bike. But I have to say that going over handlebars because of braking is not one of them. If I could venture a guess I would say that something might be wrong with your bike - bad geometry (some cheap/old bikes are unstable), tyres not pressurized enough, really bad brakes (front one working, back one not working) - if I were you I would make sure that my bike is safe. By any chance did you have a heavy backpack on your back? Or maybe you just panicked and did something you really should not do... like braking really hard with only your front brake? Please check your bike anyway.

I can't be sure. It was a friend's bike, and I was used to mountain bikes, not racing bikes.

I may have been leaning forward, I may have jammed the wrong brake. The bike may have had any of the problems you list. That combined with the manhole + hill speed was probably what did it.

I now use the public bike system in Montreal, bixi. Very convenient, and they're built like tanks, so I feel confident it won't happen again.

You need to shift your centre of gravity backwards and then you can still brake, or at least feather the brakes, hard.

Bikes are so much lighter than cars that even careful braking will stop a bike much faster than a car, even going downhill.

The same is true of motorcycyles, which is why you should allow greater following distance behind a motorcycle than a car, if you're in a car.

That's not my experience at all - cars stop a lot faster than both motorcyclists and certainly than plain cyclists (I cycle almost every day multiple times).

The thing is, in a car you can basically be unprepared, then mash the brakes when somethings wrong. It's possible that'll cause you to lose control, but in general an emergencey stop whether controlled or not will stop the vehicle very quickly without causing any direct injury.

By contrast, on a (motor)bike if you mash the brakes you'll slip or even tumble head over heels. You're not wearing a seatbelt; and furthermore your vehicle loses control a lot less gracefully.

If you're prepared, it's a different story since you can rearrange your center of mass, and get a good grip beforehand, but in an accident situation... a car stops much more quickly.

Every time I hear about someone crashing on their bike I try to learn how to reduce the chance of it happening. I train and race about 150 miles per week. Front lights like the Bontrager ION are great (for day or night) and I intend to use mine whenever I am not in a pack of riders. http://bontrager.com/products/accessories/lights.

My wife would kill me if I got hit by a car. Two days ago when I was on a bike ride (off road/cross), two somber police officers walked up to our house. My wife was sure it had to do with me getting hit by a car. They were only looking for someone who used to live near us years ago. It gave her a big scare.

A vehicle is much more visible than a bicycle. And Skyline has huge amounts of shadows from the trees, which would be exacerbated by riding on the right edge of the road where the shadows would be the deepest.

I'm curious, is a bike capable of stopping on an incline at while going at 40 mph in the same amount of time as a motor vehicle?

I'm pretty sure a bike in good condition is capable of stopping much faster than any motor vehicle, given the same speed and road. I could be mistaken, though.

Possibly, but bikes are not generally equipped with ABS and traction control. In emergency scenarios, I would wager that cars have better collision-avoidance capabilities.

When I've been going downhill with 35-40mph on a racing bike(rarely, I'm not particularly big cyclist), I've been unable to brake nearly as fast as I could on the same road with a car. Theoretically I could, but in practice the tires are very narrow and if braking anywhere near full power on non-perfect (dry, straight) conditions I could lose control while skidding, resulting in a very hazardous or deadly tumble.

Motorbikes would be a different story.

I mainly ride mountain bikes (on roads), so that might be my disconnect. The tire-width thing makes sense. I also hadn't realized before this thread that road bikes don't usually use disc brakes. Seems odd.

Disc brakes aren't always used on road bikes, because their advantages aren't excercised much - you generally don't brake so much that heat is a problem; and wheel bending isn't a problem since unlike mountain bikes, you aren't expected to hit stuff that might bend a wheel and continue riding.

For wet conditions, disc brakes would have an advantage on road bikes for others, I'm not sure.

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