Some drivers seem to resent the idea that they should have to share the road, or slow down for anyone. Even if cyclists do everything right, they're still slower than cars, and so will present at least a minor inconvenience for drivers.
In Canada the fight has gotten nasty, with governments in Alberta and Ontario putting forward legislation that could remove existing bike lanes.
While I think cycling is great - environmentally, for health, apparently for mental health - bikes and cars don't mix unless they are going approx. the same speed in 1-2 lanes.
Driving a car, bicycles are hard to see - I wouldn't be surprised if visibility in cars is specified to be sufficient to see other cars. Bicycles appear out of nowhere and disappear. Also, cyclists - no better or worse than their automobile counterparts - don't always drive well, and they do things that cars don't such as weaving through small spaces between cars; running lights as if they are pedestrians, but on the road; appearing from sidewalks and other places - really anyplace. I don't object to creative driving - as I said, (city) drivers aren't much different in their way - but it makes bikes unpredictable and hard to see. Then there's the speed difference - bikes much slower than traffic are as dangerous as cars driving that speed (again, except I can see the cars). As long as there's one lane - and if cyclists 'own the lane' and don't let cars squeeze by - it's safe: you can see the bike; multiple lanes and the bike ends up in blind spots, weaving back and forth itself, etc.
I read that in (Belgium? The Netherlands?) the law is that if there is a small (10 km/h?) difference in speed between cars and bikes, they cannot share the road.
Cyclists never do everything right, though. Contested stop signs are a prime example. For every cyclist who stops properly, 99 blaze through with attitude. They are lawless, and cause safety issues for drivers who have to deal with it.
You’ll also see them run red lights, cut off pedestrians, bike right into oncoming traffic (in the same lane, no less), cut across three lanes of without blinking. All in the name of laziness, not safety.
Bikes are different machines with different capabilities and parameters. That they aren't used like cars isn't laziness or even lack of personal safety, but maybe lack of discipline to operate as if it has the capabilities and parameters of a car.
Whatever the motive, it's still dangerous because everything on the road needs to operate in an integrated system of rules. Bikes acting like bikes are unpredictable and using different rules.
But consider the functional differences:
> Contested stop signs are a prime example. For every cyclist who stops properly, 99 blaze through with attitude.
Bicycles both stop much more quickly than cars and take more effort to restart. Restarting from a stop and accelerating to full speed takes energy and wears on tired muscles - and it's not just one intersection but 100 in one ride.
So many times I've seen bikes approach the intersection at moderate speed. That's dangerous in a car - you might need to stop short, you might hit someone or something with your 2,000 lbs metal object which could cause serious harm even at slow speeds. On a bike it's fine - you can easily stop your 200 lbs object, which is also much smaller and more maneuverable and thus avoids collisions easily, and which does little harm at slow speeds.
So the bike does the bike thing, but the car sees a car thing: The car see the bike moving at a normal rate, and assumes it will act like a car and drive right into the intersection. The car stops and lets the bike go first.
> run red lights
At lights, bikes are like (very fast) pedestrians. On foot, at least in the US and many parts of the world, if the road is clear people don't wait for the light, they just cross. Functionally, there's no reason for bikes to do differently. That's dangerous to do in a car because their size and lack of maneuverability makes them big targets and makes accidents hard to avoid, and because they cause serious harm even at slow speeds.
> cut across three lanes of without blinking
Again, bikes are much smaller (able to fit in small spaces) and much moremanueverable. It makes some sense for a cyclist; it would be far more dangerous in a car.
I do understand it takes effort to stop and re-accelerate, but isn't making effort (exercise) part of the purpose of cycling in the first place? My main objection is to cyclist failing to stop at pedestrian crossing lights: as a pedestrian, when I see a green light, I expect to cross without having to dodge moving vehicles on the road. I do check the the road to make sure that cars have stopped, but cyclists (who rarely stop at crossings, at least in London) are harder to see, as they are smaller and often obscured by the traffic.
They really don't. Even if you slam brakes and OTB on a bike you will still fly further ahead than a car doing double your speed will travel after applying brakes normally.
This is the insanity of running stop signs on a bike - you can't stop, you cannot swerve nearly as quickly as a car and you will take much more damage when T-boned than a car driver would yet you believe it's safer because:
I think that's just wrong. Bikes stop on a dime (unless going high road-bike speeds), and are much more maneuverable due to their mass and two wheels, and are effectively much more maneuverable because their dimensions make it much easier to avoid objects and fit into the many more spaces than cars can fit in.
In my experience as someone who rides a bike with hydraulic disc brakes and drives frequently, they really don't stop very quickly. I pretty much always am more confident I can stop my car faster. The bike may have a lot less mass but it also has a lot less traction and it's much easier to lock up a wheel and skid instead of stopping quickly, especially in poor conditions/on road paint. I do cycle fairly fast, but this is on a mountain bike on the road, certainly not fast compared to a fit person on a road bike.
I will give you that they're much more maneuverabile and accidents can often be avoided by putting the bike into a space in the road that a car couldn't go into.
Maneuverability of a bike suffers from the same traction issue. At the speed when you can't plant your foot to pivot around bikes need to go much slower than cars in the same corners to not skid out. Check out descends on any road race, bikes are braking to 20-30 mph in sone corners, which cars pass at full speed. Not to mention that a car can skid fairly easily on either axle, while on a bike very few can get out of the rear wheel skid and the front wheel skid is the game over.
> The bike may have a lot less mass but it also has a lot less traction
I've long wondered about that tradeoff: I've heard some (non-physics-aware) people say that heavier cars/trucks stop faster because they have more traction, but obviously there's a big tradeoff in that equation. As a guess, on a moving wheeled vehicle, 1 kg adds forward energy proportional to velocity, and downward energy constant and independent of velocity? And maximizing that tradeoff would seem to be an engineering goal in order to minimize muscle/gas expenditure. (I'm sure it's well-known but I'm too lazy to look up the details.)
That ignores road/tire and air resistance which are proportional to velocity. And I suppose a key question is the degree to which traction depends on vehicle weight: maybe it depends more on tire and road characteristics, for example. Certainly ice or some kind of low-grip tire would be a big factor.
And that ignores locking up the wheel, as you pointed out.
Driving a car, bicycles are hard to see - I wouldn't be surprised if visibility in cars is specified to be sufficient to see other cars. Bicycles appear out of nowhere and disappear. Also, cyclists - no better or worse than their automobile counterparts - don't always drive well, and they do things that cars don't such as weaving through small spaces between cars; running lights as if they are pedestrians, but on the road; appearing from sidewalks and other places - really anyplace. I don't object to creative driving - as I said, (city) drivers aren't much different in their way - but it makes bikes unpredictable and hard to see. Then there's the speed difference - bikes much slower than traffic are as dangerous as cars driving that speed (again, except I can see the cars). As long as there's one lane - and if cyclists 'own the lane' and don't let cars squeeze by - it's safe: you can see the bike; multiple lanes and the bike ends up in blind spots, weaving back and forth itself, etc.
I read that in (Belgium? The Netherlands?) the law is that if there is a small (10 km/h?) difference in speed between cars and bikes, they cannot share the road.