Fahrenheit531 

I'm curious to hear what people's take on this might be.

Seattle cops ticket bicyclists for speeding near elementary school

I'm on the side that says this is a good thing. We're talking about elementary school kids; I've got one of those, and they're unpredictable little buggers. A bike blazing through that zone on a downhill can do a heck of a lot of harm in that situation.

Thoughts?

Matariki

I fine with this as well. I wonder about the ability of a radar gun to accurately capture the speed of a bike, but it's probably right. On one of my commuting routes they have a radar speed checker that matches my cyclometer well.

Reading the comments was interesting as always.

Leebo

Not saying speeding is OK on a bike through that kind of area, However, bikes can usually stop much faster and likely to have a better sense of surroundings and awareness. MA bike law is $20.00 max for fines.

WebFootFreak

I'm in full agreement as well. If you're taking a lane on a public road, then you are subject to the rules of the road.

Keith99

Dead wrong. Bikes cannot stop as fast as a car going the same speed.

Leebo

I usually ride with my hands on my brakes, esp. with traffic around. Reaction time, plus braking distance, my bike would stop faster. Disc bakes and assuming clean, dry pavement, every time. Prove me wrong.

Fahrenheit531 

Quote:

Originally Posted by Matariki

Reading the comments was interesting as always.

Hahahaha Never a dull moment in the comments section of an article, though I often want to put a hammer through my screen.
This is true, and I've got first-hand childhood experience on the stopping part. When I was in kindergarten, maybe first grade, I was playing in the front yard and one of my matchbox cars fell off the curb into the street. I looked up the street and there was a guy approaching on a ten speed. After taking a couple of seconds to figure out if I had enough time to grab my car or not (whoops), I stepped off the curb in front of him. He jammed the brakes and went over the handlebars, I was fine, mom helped him clean and bandage the damage, and that was pretty much that. But this situation had basically unlimited visibility: no cars on the street and a clear Arizona summer day, which means I'm sure he had at least considered the possibility of my doing something stupid. But looking at the picture that accompanied the article, I see a lot of blind spots that may render a bike's stopping power irrelevant at 25-30 mph.

I think this makes me a "situational enforcement" guy, as I have no problem with willful disregard for the posted limit in a lot of places.

ItsJustMe

Actually at any given speed, cars can stop much faster than bikes.

I'm all for enforcing ALL the laws in school zones. Damned places are some of the most dangerous spots on the roads around.

Leebo

Unless you drive with 2 feet, how long does your car travel taking your foot from the gas to the brake? Some quick googling came up with 35-45 ft for a bike and anywhere from 60-90 ft for a car at 30mph.

Keith99

Unless your hands are already on the Brake levers it takes a longer to grip them than it does to move your foot while driving.

I'd say bikes only gain in a situation where there is a moderate concern regarding needing a quick stop. At both no concern and maximum ready a car wins on reaction time.

Fahrenheit531 

I seem to have reopened the portal to "Braking: Bike v. Car" hell.
Sorry.
You can be assured this was not the plan (cf. Law of Unintended Consequences).

dougmc

Don't google -- do the math yourself, it's not hard. But if you must google, at least make sure you get both statistics from the same site where they calculated both with the same assumptions made.

Not everybody drives with their foot on the brake, and not everybody rides with their hand on the brake either.

But once the brake is engaged, a car can stop faster than a bike, as it's not limited by the tendency to endo, and having the front wheel skid isn't as disastrous as it is is on a bicycle so you can safely get closer to the limit in limited traction situations (in dry pavement situations, the endo tendency is the limiting factor for a standard upright bike (tandems and LWB recumbents are different.))

A standard upright bike with a front brake on dry pavement can brake at about 0.6 g's, maybe 0.7 g's if you throw your butt as far back as possible. A typical passenger car can do around 1.0 to 1.1 g's and some sports cars can do 1.3 g's (and things like Formula 1 can do up to 5 g's thanks to their aerodynamic downforces.)

Must be nice. Fines on a bicycle are generally the same as they are in a car in Texas, so 1 mph over the speed limit in a school zone is $178 minimum, car or bike. Fail to stop for a stopped school bus? $552 minimum, car or bike.

RobertHurst

Max deceleration on an upright bike is .85-.89 g's. Max deceleration of upright bike if rider remains static and seated is .6-.7 g's.

dougmc

I've found that these devices can usually accurately determine the speed of my bicycle (and we all see them as a challenge), HOWEVER if there is a car behind me, it tends to pick up the car's speed rather than mine, even if I'm closer.

If the guys wanted to fight the ticket, they could claim to be going right at the speed limit, that the radar gun must have picked up a car behind them. Might work, but probably not -- without physical evidence, the judges tend to favor the cop rather than the guy who got the ticket in traffic court, no matter how plausible their story is.

That said, I have no problems with the police ticketing cyclists for exceeding the speed limit. In a non school zone they might be proud of the ticket and frame it, but in a school zone probably not.

dougmc

There's a fair amount of disagreement in the exact figure, though it'll depend on the exact geometry of the bike and the dimensions of the rider -- there is no single figure that will cover all upright bicycles, and the variance is more than the 5% you gave.

This analysis finds 0.61 g's on saddle, 0.68 g's off saddle, and does reference both of the two following analyses.
Same author, basically the same thing, but in a different format.
Forrester claims 0.67 g's in the saddle is typical in section 9.17, and says that moving one's butt back will "achieve a very small increase in this". Forrester doesn't get into the math here, however like the other links do.
Riel says 0.63 g's in saddle, 0.83 g's out of saddle (but note that the first link finds a flaw in his analysis.)
I don't have it in front of me, but I recall that Bicycling Science gave a figure between 0.6 and 0.7 g's. (I guess I need it in front of me.)

I either way, I can't find anybody claiming as high as 0.89 g's except you, though of course with a long bike and a short rider (especially one that's bottom-heavy -- more weight in legs, less weight in arms (but still long arms), head and torso) you might be able to achieve that.

But either way .. 0.89 is still less than 1.1. Cars can stop faster than most upright bikes. A tandem or LWB recumbent could probably come pretty close to what a car could do, but even then the car could more safely push the envelope -- where the bike would crash if the front wheel skids, the car just wouldn't stop as fast.

edit: I now have Bicycling Science, 2nd edition, by Frank Rowland Whitt and David Gordon Wilson in front of me. I don't want to type out the entire section, but the key part is "Another conclusion from this calculation is that a deceleration of 0.5g is almost the maximum that can be risked by a crouched rider on level ground before he goes over the handlebars." (He then refines the calculation and finds the maximum deceleration for the case he was giving -- 0.56 g's. Note that he doesn't consider throwing one's butt back behind the seat.) He then adds this -- "Tandem riders and car drivers do not have this limitation; if their brakes are adequate they can theoretically brake to the limit of tire-to-road adhesion. If the tire-to-road coefficient of friction is 0.8 they are theoretically capable of a deceleration 0f 0.8g, which is 60% greater than that of a bicyclist with the best possible brakes. For this reason -- and many others -- bicyclists should never "tailgate" motor vehicles."

(I don't have an explanation for the discrepancy of the 0.8 coefficient of friction between pavement and tire and passenger cars being able to stop at more than 0.8 g's. Air resistance? Downforce? The highest coefficients of friction are actually higher than that? But either way, the 1.0+ g's they can pull is easily verified by simply doing it.)

sam21fire

Same rules, same rights, same responsibilities, same consequences for breaking the law.

kjmillig

Speeding? Ticket. Get caught violating rules of the road? Ticket. Makes perfect sense.

dynaryder

I'm ok with slowing bikes down through a school zone,but they do need to have one of those signs that say how fast you're going. Bikes don't come standard with computers,and aren't legally required to have them. How can a cyclist tell the difference between 20 and 25mph?

CB HI

Many, maybe most police departments do not issue speeding tickets unless the driver is going more than 9 mph above the speed limit. I doubt this grace is not being given to cyclists. Ticketing cyclists is fine if motorist are being ticketed for going 2 mph over the limit as well, but for some reason I doubt Seattle police are not treating motorist and cyclists the same.

dougmc

Just to be clear, I don't think cars are generally required to have them either. Maybe there's some standard that requires that new cars be equipped with them, but in general if yours breaks there's nothing requiring that you repair it.

Also, speed limits exist just about everywhere, not just in school zones. Are you suggesting that every place needs a radar device to give you your speed in order to enforce them?

In any event, if you don't know your speed, don't worry too much about it -- the cop will put it on the ticket. Can't tell if you're exceeding the speed limit or not? They sell devices that will tell you how fast you're going. They're not expensive, and they're highly accurate when set up properly.

Certainly, the speed limits don't apply only to those who know how fast they are going -- they apply to everybody.

Pretty easily, actually. But if you need to know your exact speed -- get a computer.

dougmc

Police generally are more strict about the limits in school zones. I don't think they usually ticket for one mph over, but five mph over? A ticket is likely.

jon c. 

Most places I've lived used different standards for school zone tickets and issue them at 3 mph over.

turbo1889

That's an excellent question that I can answer for you. If you know your gears and your tire size you can calculate how fast you will be going in each gear by pedal cadence RPMs, a technique I personally and regularly use on most of my commuting bikes where I don't want to strap yet another piece of electronics with batteries and wires to my bike and skip the spedo and just concentrate on lights.

For example on my "bus bike" (for when I take the bus with the bike in the rack between towns and then ride around town on the bike doing my errands) it has a single 48t front chain wheel with a 13t,14t,15t,16t,18t,21t,26t,34t custom ratio 8-speed free-hub cassette in the rear when I'm pedaling at a cadence of 90-RPM which is right in the perfect strong power zone for me personally and I can easily "feel" that pedaling speed where the pedal cranks go around one and half times ever second if I'm in second gear (gear I start out in when pulling away from a dead stop) and "spooled up" on my pedaling to that 90-RPM zone that is my best zone I'm going about 13-mph, then its about 16-mph for third gear, about 18.5-mph for fourth gear, about 21-mph for fifth gear, about 22.5-mph for sixth gear, about 24-mph in seventh gear, and finally almost 26-mph in eighth, high gear. Thus I can know my speed by what gear I am in based off of my pedaling speed when I'm "in the zone".

This can be done with any bike and you don't even have to run the math if you happen to have one of those speed display signs they set-up along the road. Just make multiple runs past each time doing your own personal "fast but strong" optimum pedal power zone in a different gear. Pretty soon you can tell how fast your going just by which gear you are in and how fast you can feel that you are pedaling. Heck you can get some feel for judging speed by your gearing even without a handy sign put up by the local boys in blue if you ride long enough and get a feel for the bike and are conscious of what gear you are in.





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As to the actual topic of the main discussion raised by the OP:

Well, I have no objections to cops giving tickets to cyclists when they break the rules too, especially when it is a situation that could actually be a hazard, I would agree that "scorchers" (look up that term in direct reference to cyclists, its over a hundred years old) in an elementary school zone would definitely qualify as a potential real hazard and it isn't just law enforcement for the sake of enforcement.

That said, I do not deny that I am far less careful about not speeding on a cycle especially a pedal-only cycle then with any other vehicle and I know that I could have been issued such a ticket myself on more then one occasion. If I do ever get one then I'll probably deserve it and it might even cure me of the bad habit. So far I haven't gotten a ticket for speeding on a bicycle but I did get one many years ago for having studded snow tires on my bike in the Spring after the date when studded tires are no longer legal. I was able to talk the price tag down with the judge based on the logic that I certainly wasn't creating as much road damage with studded snows on after the legal date then a car would with studded snows but I still paid the ticket, just not full price, because I knew I was legitimately busted.

CB HI

Cops are ticketing cyclists on a DOWN HILL.

B. Carfree

If I were to ever get a ticket, I will thank the cop who gives it to me (assuming I was breaking the law), pay the fine and move on. I don't deserve any special consideration or break. It's not like the laws are difficult to understand or follow. If I choose to roll a stop sign or exceed the speed limit, then that's my decision and, as a big boy, I'll take the consequences without whining.