Obviously, most accidents happen while the bike is in relatively high speed, which
1) makes it harder to respond to unexpected situations,
2) makes it harder to come to a stop,
3) worsens the impact (obviously)

If I maintain a reasonably medium or low speed on the city street, it will be less risky? (Of course there are occasions when faster means safer, such as when you are avoiding a car coming right at you: in that case beling slow would mean waiting to be hit )

I say "reasonably" because I don't mean to be so slow that I am blocking the traffic or becoming an odd ball on the street.

There is no sensible advice one can give about this other than to adjust one's speed to the conditions. At times, in town, that can mean travelling as fast as the fairly slow-moving traffic, because that is the way to take the lane and ensure both visibility and freedom to manoeuvre. But certainly it makes sense to moderate one's speed in many urban situations. I see a lot of commuters cycling as if they were time-trialling and taking far too many risks - both with their own safety, and that of pedestrians - as a result.

But I wouldn't agree that it is obvious most accidents happen at relatively high speed. I believe the statistics show that most accidents to cyclists occur at junctions, and in some such cases the cyclist will be just moving away having been stationary. Being aware of the vehicles around you, and how to minimize the risks they pose to you, are the critical factors here.

IME, going slowly makes you look inexperienced and submissive. Going as fast as you safely can asserts your status as a vehicle, and people are less likely to try to push you around.

Sorry, but no. Most drivers can't tell the difference between a cyclist doing 12mph and a cyclist doing 20mph relative to their own speed.
Don't confuse riding fast with riding assertively and confidently.

I used to ride fast, twenty years ago. I've slowed down.

I think that when a motorist wants to pass, he doesn't care about the speed limit, nor does he care about your safety.

I ride slow and watch my mirror. I go slow enough that I can pull over to the curb.

+1

It's easy to fall into inappropriate speed habits. Just because we have a motor that can manage speed X doesn't mean we have to constantly show it off.

I observed what could have been a very serious accident this weekend, as in getting someone killed.

A careless biker towing a child on one of those third wheel add-ons started to cross a street with a marked bike lane and did not notice someone coming along in the bike lane at high speed. There were others crossing, other bikes in the bike lane going different speeds, kids, groups of cyclists, whatever. Fortunately there were no cars in the street at the time and the fast biker was able to avoid a collision by a small margin. I would guess the guy in the lane was coming down a small curving hill at about 20mph+.

Now the issue here is that one idiot made a really bad mistake at not looking out for traffic properly but also that another idiot insisted on maintaining full speed into a zone crowded with people at an intersection where many bikers and pedestrians cross from a MUP across a N-S street to head E on a street that originates E bound in a T at that intersection, that is major bike route, auto route, flanked with sidewalks and so on. The fast biker was S bound in a bike lane on the N-S street and has right of way. All of this on a very pleasant Sunday afternoon. None of the bikes, walkers, or cars have traffic controls except a stop sign on the E-W street that stops W bound traffic from entering the N-S street, a factor irrelevant to the possible accident.

The point is, right of way or no right or way, excessive speed for the conditions is very dangerous. Approaching an intersection crowded with crossing bikes and pedestrians including parents with children, dog walkers, etc., etc., justifies slowing down even for those who have right of way.

As others have said, there is no one safe speed. Sometimes one is safer to hammer along at 33 mph, like on a 35 mph multi-lane road, and sometimes it is best to chill. Assertive and attentive to changing conditions are important keys.

Just don't bomb down the hill in the bike lane. Take the lane on all downhills that take you over 20mph. If the traffic is moving too fast, waiting for gap in traffic or just enjoy the downhill at reasonable speeds in the bike lane.

Where does this assumption come from? ~ 1/3 - 1/2 of bike crashes are the 5-15 age group, (~14% of the population.) I don't think this is a particularly fast group.

Please cite your sources. This is not obvious at all, and I would tend to disagree with your assertion.

This would depend entirely on your bike handling skills. You should never exceed what is safe for your level or expertise, nor what the situation dictates.

While this is a simple matter of physics, stopping is not always the safe thing to do. Again the situation dictates what is safe. I would suggest that stopping on a 35+ mph multilane while you are attempting a left turn and are in lane would not be a safe choice...the examples are endless. Likewise, stopping essentially eliminates your ability to maneuver, so again it depends on your bike handling skills.

Also a simple matter of physics, but getting run over from behind because you chose to stop, or significantly slow down in a higher speed lane (whether from a car or another bicycle) is not my idea of lesser impact.

There is no one size fits all. As many posters to this thread have indicated, slow is not better, it is just an option that is dictated by the situation in which you find yourself riding.

It is the same with driving a motor vehicle, speed is dictated by law and limits, but in all cases, what is safe and reasonable at the time with the conditions present.

HTH
zac

Happy to see this being discussed. I have mentioned several times that I do believe that there are situations where slower speed will make you safer. Very few people usually agree. Slower speed may help you being more predictable for motorists among other reasons.

Here is a situation where I (and quite a few other cyclists) decide to be close to the door zone because of traffic and very a poor street surface in the center of the road. Being in the door zone is dangerous, therefore many will go slower to minimize the risk. Taking the lane will block faster traffic and lead some to pass you unsafely.

In other situations you may be able to take the lane and go at a high speed (in a high traffic but low speed urban area) and just truly be another vehicle that seemlessly flows with traffic.