Supported Lejog goes Off topic

[Steady rider]

The mirror topic may be worth extra research, for example, how many views per km on average, say 4 , time to view - say 0.5 seconds, say the above works out to be 4 x 0.5 = 2 seconds per km, say the average riding speed is 25 km/hr, 1 km in 2.4 minutes. From this guess work, using a mirror could take on average 2/144 seconds of the time, 1.4% of the riding time.
I assume this may lead to missing road surface deflects in some cases, that could be a disadvantage.

The positive and negative aspects may be difficult to be completely assess. In the cases where a vehicle may be passing close, the view time may be extended and risk of missing a road surface defect increased.

[horizon]

The positive and negative aspects may be difficult to be completely assess. In the cases where a vehicle may be passing close, the view time may be extended and risk of missing a road surface defect increased.

Yes, though of course a mirror user would say it's even worse if you physically look round.

But take another scenario: it's a good road ahead, cars are coming frequently but not all the time, you glance at your mirror and the road behind is clear. Or you clock the vehicle in the distance (allowing for distortion). You can be much more relaxed, you have a sense of what is coming, you can position yourself better. The idea of just hunkering down and keeping your fingers crossed while vehicles thunder by just isn't my sort of cycling.

Not everyone will want to do this. But I always feel that it gives me a much better sense of my relationship to the other vehicles on the road.

And BTW, I might not look round but the driver is very aware that I know what he/she is doing from my road position and hand signals.

[reohn2]

The mirror topic may be worth extra research, for example, how many views per km on average, say 4 , time to view - say 0.5 seconds, say the above works out to be 4 x 0.5 = 2 seconds per km, say the average riding speed is 25 km/hr, 1 km in 2.4 minutes. From this guess work, using a mirror could take on average 2/144 seconds of the time, 1.4% of the riding time.
I assume this may lead to missing road surface deflects in some cases, that could be a disadvantage.

That's a wrong assumption,I use a RVM,and rarely hit potholes or potentially damaging/uncomfortable road irregularities and I rarely puncture.In fact on a couple of occasions been told I'm a 'safe wheel' to follow in a group.
I don't know how often I check the mirror,but it's very regular in traffic,less so on country roads.It's also handy when approaching such obstacles as you mention,as multiple glances can be used to check out traffic behind and give them more notice if I need to move to primary to avoid such obstacles,or when approaching other manoeuvre points ie; junction,parked car,etc,before the 'lifesaver' check.

The positive and negative aspects may be difficult to be completely assess. In the cases where a vehicle may be passing close, the view time may be extended and risk of missing a road surface defect increased.

The mirror check is but a glance,and not even a need to move the head(though making it obvious by moving my head in certain situations can indicate to following traffic that you've seen them),it's merely a flick of the eyes,similar to when driving.
It needs but a glance or two to estimate both the existence of following traffic and their speed,one becomes tuned to using the RVM for such information,almost whilst still looking ahead,again much as you would when driving.

As I say you make a wrong assumption in thinking anything but a split second of time is used to survey the RVM's information.

IMHO there are some absolute anti RVM cyclists dismissing them as unnecessary,and I've had one or two of these cyclists tell me so,as if I'm breaking some unspoken rule of cycling,
I find myself laughing in the the face of such people's arrogance and in most cases ignorance,they can go their own sweet way and don't let me stop them,it's their choice but but when they begin to try to tell otherwise they can go and whistle.
My attitude in an ever increasingly hostile road environment is to have as much information of the traffic around me as possible.
IME of both riding with and without,a RVM is an excellent tool for such assessment,much like any other vehicle I've ever ridden or driven on the roads.

[Steady rider]

http://deepblue.lib.umich.edu/bitstream ... sequence=2
some data on fixation times are provided, the mean is fairly low about 0.29 secs. A car mirrors - may be either side or overhead and the time may vary slightly. A mirror on a bicycle may be similar to using a side mirror on a car or motorcycle mirror perhaps? If individuals vary in the time they take to look into a mirror may be also be a factor.

I generally use hearing at an indication of traffic from behind, most HGV you can hear from a distance and if needed can be shoulder check. If two groups of cyclists, one with mirrors and the other without, kept detailed records of total mileage, number of falls, near misses and accidents, the results may indicate some difference.

I assume this may lead to missing road surface deflects in some cases, that could be a disadvantage.

That's a wrong assumption

I think it would need proving one way or the other, it may be so low an effect as not to be significant. I am fairly sure if I spent more time looking into a mirror I would have a higher risk of missing something in front or have a delay in my reaction to deviating around a pothole for example. In short I would probably need to see some research on this topic before changing my view.

[reohn2]

I think it would need proving one way or the other, it may be so low an effect as not to be significant. I am fairly sure if I spent more time looking into a mirror I would have a higher risk of missing something in front or have a delay in my reaction to deviating around a pothole for example. In short I would probably need to see some research on this topic before changing my view.

In short you're clutching at straws IMHO,the time spent looking at a RVM is absolutely minimal,so minimal as to make no difference to forward observation.
Consider this,cars and motorcycles travel much,much faster than bicycles,and I don't see them having problems with forward observation causing problems,I do witness drivers having such problems but I suspect it isn't RVM's being the cause of it.
So given that drivers/riders of much faster vehicles don't have any problems using RVM's and after 45+ years riding motorcycles and driving cars on the roads,plus 15 years riding bicycles with a RVM(concluding a RVM is better for keeping me better informed of traffic behind) and 35+years riding a bicycle without one.
And never experiencing any of the problems you envisage,my conclusion is still the same,that you make a wrong assumption when you claim RVM use on bicycles compromises their safety or their forward observation in anything other than a minute amount of time as to make no difference.
YVMV.

[kwackers]

Consider this,cars and motorcycles travel much,much faster than bicycles,and I don't see them having problems with forward observation causing problems,I do witness drivers having such problems but I suspect it isn't RVM's being the cause of it

Faster is the key. You don't need to look backwards anywhere near as much since there's little difference in speed between the yourself and the vehicle behind. As a rule other than the occasional brief look to keep track of traffic changes you only *really* look when you're about to perform a manoeuvre.
OTOH a bicycle having traffic approaching the rear at speed in some ways is a completely different animal.

One of the great 'myths' is that people make good observers, checking mirrors doesn't mean you're seeing just as looking forward doesn't mean you're seeing. It's easy to buy into the myth that you've checked your mirror and therefore are aware of what's happening behind.
SMIDSY isn't just caused by people not looking, it's also caused by people not seeing and there's absolutely no reason that looking in a mirror is immune from that.

The reality is you need to actually look and not glance to make a conscious appraisal of what's happening behind. This is more so with bicycles because the scene behind you is changing rapidly, cars and motorcycles have an advantage here in that the scene doesn't change much and so they can rely on their subconscious to alert them to changes at which point they can look properly, something cyclists don't have the luxury of.

[Steady rider]

reohn2 » Wed Jan 06, 2016 3:49 pm, in reply
At least from your experience and judgement you believe they provide a benefit.

Figure 1. Fixation Distributions
(Source: Rockwell and Rackoff, 1969) from the link,
provides details of fixation times, 0.083 to 1.47 seconds, some people may be able to view the mirror in a very short time period, other may take longer.
At 20 mph, 32km/hr/ 8.8m/s, 0.083 equates to 0.74m of travel roughly and at 1.47 secs 12.9m
Assuming this range may occur for cyclists, some may view the mirror in less than a 1 m of travel it seems and others may take more than 10 m of travel. The information from the view has also to be considered.
I think we have the case of you believing and I am not convinced, that is fine I suppose.

[Vorpal]

People use mirrors more extensively driving motor vehicles at 70 mph. It's not only not considered a problem (sorry about the double negative), but a legal necessity.

[irc]

The reality is you need to actually look and not glance to make a conscious appraisal of what's happening behind. This is more so with bicycles because the scene behind you is changing rapidly, cars and motorcycles have an advantage here in that the scene doesn't change much and so they can rely on their subconscious to alert them to changes at which point they can look properly, something cyclists don't have the luxury of.

Unlike cars and motorcycles, cyclists on rural roads or quiet urban roads can usually use their ears to tell them when a mirror check is needed.

In the rare circumstances when mirror checks are not advisable due to road and traffic conditions that merely puts the RVM using cyclist back in the position other cyclists are all the time. Because a mirror can't be use 100% of the time is no reason not to use it where possible.

[reohn2]

Faster is the key. You don't need to look backwards anywhere near as much since there's little difference in speed between the yourself and the vehicle behind. As a rule other than the occasional brief look to keep track of traffic changes you only *really* look when you're about to perform a manoeuvre.
OTOH a bicycle having traffic approaching the rear at speed in some ways is a completely different animal.

You're reinforcing my beief in RVMs

One of the great 'myths' is that people make good observers, checking mirrors doesn't mean you're seeing just as looking forward doesn't mean you're seeing. It's easy to buy into the myth that you've checked your mirror and therefore are aware of what's happening behind.
SMIDSY isn't just caused by people not looking, it's also caused by people not seeing and there's absolutely no reason that looking in a mirror is immune from that.

I make no claims for better seeing only a better ability to see,whether someone chooses to see when they look is another matter.

The reality is you need to actually look and not glance to make a conscious appraisal of what's happening behind. This is more so with bicycles because the scene behind you is changing rapidly, cars and motorcycles have an advantage here in that the scene doesn't change much and so they can rely on their subconscious to alert them to changes at which point they can look properly, something cyclists don't have the luxury of.

You're reinforcing my belief in RVMs again
It's because of the constantly changing rearward scene,due to speed differential and my vulnerability on the bike,that I need to keep an eye on it*.

*a figure of speech not literally keeping one eye on the RVM

[kwackers]

You're reinforcing my beief in RVMs

I'm not trying to destroy it... I think they're useful, if nothing other than to make one feel 'safer'. My interest lies in trying to figure out what the pluses and minuses are and how useful they really are and whether they genuinely contribute to safety or not...

[reohn2]

reohn2 » Wed Jan 06, 2016 3:49 pm, in reply
At least from your experience and judgement you believe they provide a benefit.

Figure 1. Fixation Distributions
(Source: Rockwell and Rackoff, 1969) from the link,
provides details of fixation times, 0.083 to 1.47 seconds, some people may be able to view the mirror in a very short time period, other may take longer.
At 20 mph, 32km/hr/ 8.8m/s, 0.083 equates to 0.74m of travel roughly and at 1.47 secs 12.9m
Assuming this range may occur for cyclists, some may view the mirror in less than a 1 m of travel it seems and others may take more than 10 m of travel. The information from the view has also to be considered.
I think we have the case of you believing and I am not convinced, that is fine I suppose.

I'm more likely to be in the 3m camp,and when I'm about to look in the mirror I've surveyed the road ahead for anything that may be a hazard,if it's moving ie;vehicle,vegetable,animal,or mineral, or not ie; pothole,ironworks,etc which requires immediate attention to navigate,the mirror won't get my attention until the hazard,perceived or otherwise is delt with first.
I'd say that's pretty much standard practise for mindful road use,RVM or not.

If I need to spend any amount of time looking behind in my RVM ie;long gaze,which is more likely to watch something of greater concern than what's happening up ahead ie; another member of a group has stopped or lost the wheel,etc.I'll have checked and will keep checking if it's safe in front or if I've wandered off line or some such.
TBH not wanting to sound pompous but if I can't check and scan the road in front enough to take my eyes of it for even as much as 2 full seconds without being aware of any potential threats I'd question my cycling skills,that said there are times when I can't afford that amount of time from looking forward,ie heavy rushour traffic approaching complicated junctions,etc.

As I said previously YVMV,but I can't see any scientific reasons for your viewpoint.I don't know if you've ever used a RVM on a bicycle to support you beliefs,but there's more than half a dozen people who've asked me if one helps,of the four that have fitted them all four have responded in the positive.
One person who fitted one then removed it,when I asked him why said "it didn't look right",an ex racer would you believe .
Fashion a master that can't be satisfied

[reohn2]

You're reinforcing my beief in RVMs

I'm not trying to destroy it... I think they're useful, if nothing other than to make one feel 'safer'. My interest lies in trying to figure out what the pluses and minuses are and how useful they really are and whether they genuinely contribute to safety or not...

The ability to see behind without turning my head that way is only ever a plus.
Where it can become dangerous is when it's view is trust instead of the 'lifesaver' over the should look.

[reohn2]

Unlike cars and motorcycles, cyclists on rural roads or quiet urban roads can usually use their ears to tell them when a mirror check is needed.

In the rare circumstances when mirror checks are not advisable due to road and traffic conditions that merely puts the RVM using cyclist back in the position other cyclists are all the time. Because a mirror can't be use 100% of the time is no reason not to use it where possible.

+1
The ears plus the RVM can help enormously,but on busy roads the RVM can be that extra sense instead of hearing which has been crowded out by other road noise.

[deliquium]

I'm a stand up and be counted right on pro mirrorist (Mirrycycle), obviously you know what we really NEED is more technology

https://youtu.be/7lCQN8DaelY