This door zone thing...

[gaz]

I mentioned this in another thread recently, but I think it is worth mentioning again here. If you are riding just outside the door opening zone, then you are in secondary position. Primary position is the centre of the main traffic flow, so if the main traffic flow is passing parked cars and leaving one car door's width, then primary position will be about 2.5 to 3 metres away from the parked cars.

It is sometimes important to realize this if you want to avoid idiots squeezing through when you are passing parked cars. I illustrated that in this blog post.

It can be difficult to do, and you can't eliminate every single problem with impatient drivers, but the key is to plan well in advance, check back and if possible make eye contact with any following drivers (though it's not alwasy possible), signal clearly, do not make sudden movements, and keep looking back. Then thank the patient driver with a thumbs-up.

It really depends on the road. For example, the vehicles in that lane travel very close to the parked cars due to the nature of the road. A secondary position on that road still puts you well within the door zone and a primary position puts you in a position where you might still need to swerve to avoid a door.

But a secondary position on this road keeps you out of the door zone but still allows for vehicles to pass you 'safely'.

 

[John90]

I mentioned this in another thread recently, but I think it is worth mentioning again here. If you are riding just outside the door opening zone, then you are in secondary position. Primary position is the centre of the main traffic flow, so if the main traffic flow is passing parked cars and leaving one car door's width, then primary position will be about 2.5 to 3 metres away from the parked cars.

It is sometimes important to realize this if you want to avoid idiots squeezing through when you are passing parked cars. I illustrated that in this blog post.

It can be difficult to do, and you can't eliminate every single problem with impatient drivers, but the key is to plan well in advance, check back and if possible make eye contact with any following drivers (though it's not alwasy possible), signal clearly, do not make sudden movements, and keep looking back. Then thank the patient driver with a thumbs-up.

Very good, thanks.

 

[MrHappyCyclist]

It really depends on the road. For example, the vehicles in that lane travel very close to the parked cars due to the nature of the road. A secondary position on that road still puts you well within the door zone and a primary position puts you in a position where you might still need to swerve to avoid a door.

I agree, it always depends on the particular circumstances. Perhaps I should have put a "normally" in there. (I did say: "if the main traffic flow is passing parked cars and leaving one car door's width", though.)

Having said that, I think the road you showed illustrates my point very well. If you move just a little further down, to here, I think primary position is in the centre of the black SUV, a couple feet to the left of the centre line. Staying just outside the door zone in this case, which would be level with the left side of the SUV, might encourage people to overtake unsafely, particularly when there is oncoming traffic.

But a secondary position on this road keeps you out of the door zone but still allows for vehicles to pass you 'safely'.

Of course, in the absence of any other factors, secondary position is usually the right place to be if there is room for vehicles to pass safely.

That's another badly designed cycle lane there. To keep out of the door zone, you'd need to ride along the dashed line, which is likely to annoy the more impatient motorists who think we should be in the middle of the cycle lane, and is also likely to encourage close passing. Such cycle lanes should be made illegal.

[EDITS: I'll get it right eventually!]

 

[Origamist]

I mentioned this in another thread recently, but I think it is worth mentioning again here. If you are riding just outside the door opening zone, then you are in secondary position. Primary position is the centre of the main traffic flow, so if the main traffic flow is passing parked cars and leaving one car door's width, then primary position will be about 2.5 to 3 metres away from the parked cars.

It is sometimes important to realize this if you want to avoid idiots squeezing through when you are passing parked cars. I illustrated that in this blog post.

The difficulty is that people have different concepts of the door zone. For some people riding to 3 feet from parked vehicles is ample, for others 4 foot is fine, for others, only 6 foot is sufficient etc.

"Flinch room" also varies from person to person - the car door might be 3ft wide, but if it is flung open when you are only a few meters away and your riding 4ft away from the door, will you instinctively deviate, how about at 6ft?

There is also the problem of how you measure the distance - I take it from my widest point - usually my left elbow and measure guestimate it to the vehicle's wing mirror. Others measure it from where their front tyre tracks.

I avoid riding down the residential road I live on (we live at the end of the street) as there is on street parking on both sides and speed humps (not sinusoidal). I take the long way round to avoid impatient drivers and only have to cycle 30m on my road using the longer option. Route choice is important when considering how to deal with door zones and traffic.

 

[MrHappyCyclist]

The difficulty is that people have different concpets of the door zone. For some people riding to 3 feet from parked vehicles is ample, for others 4 foot is fine, for others only 6 foot is sufficient etc.

"Flinch room" also varies from person to person - the car door might be 3ft wide, but if it is flung open when you are only a few meters away and your riding 4ft away from the door, will you instinctively deviate, how about at 6ft?

There is also the problem of how you measure the distance - I take it from my widest point - usually my left elbow and measure guestimate it to the vehicle's wing mirror. Others measure it from where there front tyre tracks.

I avoid riding down the residential road I live on (we live at the end of the street) as there is on street parking on both sides and speed humps (not sinusoidal). I take the long way round to avoid impatient drivers and only have to cycle 30m on my road using the longer option. Route choice is important when considering how to deal with door zones and traffic.

Yes, I agree. I try to keep at least 1.5m of clear space between the sides of the parked cars and the nearest point on my bike, because open doors can extend 1.3m on a 2 door car, but I can only guess the distance of course. I think I am probably often still closer than I should be, and certainly a lot closer than that US training video suggests, but I am always surprised by how close most other cyclists I see go past.

Unfortunately, I have to travel along such a residential road to get to my home, and often have to be in the door zone to stay clear of oncoming traffic.

I think we are talking about rules of thumb and principles here, rather than hard and fast rules. Every situation has to be assessed to try to minimize the risks as much as possible.

 

[Angelfishsolo]

Yes, I agree. I try to keep at least 1.5m of clear space between the sides of the parked cars and the nearest point on my bike, because open doors can extend 1.3m on a 2 door car, but I can only guess the distance of course. I think I am probably often still closer than I should be, and certainly a lot closer than that US training video suggests, but I am always surprised by how close most other cyclists I see go past.

Unfortunately, I have to travel along such a residential road to get to my home, and often have to be in the door zone to stay clear of oncoming traffic.

I think we are talking about rules of thumb and principles here, rather than hard and fast rules. Every situation has to be assessed to try to minimize the risks as much as possible.

Spot on. That is why these things are guidelines and not rules.

 

[Red Light]

[/left]Ah, the debunked Helsinki report trying to make a comeback again.

I wouldn't rely on David's blog for debunking. For David cycling is dangerous and the only solution is segregation so he is bound to say "The problem lay with the "Finnish Study", not with our designs"

His debunking is nonsense. For example he says that the cycling death rate in Finland is 20 per bn km, one third of the UK rate and claims that must be down to the segregated tracks. The UK rate is actually 24 per bn km which makes Finland ~80% of the UK rate, not one third. He then says that the Finns cycle seven times as far as the Brits. Now applying the standard Safety in Numbers factor seven times as much cycling should make cycling over 3 times safer, not 20%. With those numbers cycling Finland should be down at 8 deaths per bn km, not up at 20. So the question is why is it so high in Finland despite many more people cycling?

I would not claim its all down to the cycle tracks but David's diatribe is no basis for ignoring the experience of someone who is responsible for 1,000km of two way cycle paths and whose advice is

"It is hard to imagine that our present two-way cycling network could be rebuilt. But in those countries and cities which are just beginning to build their cycling facilities, two-way cycle paths should be avoided in urban street networks."

 

[Tommi]

I wouldn't rely on David's blog for debunking. For David cycling is dangerous and the only solution is segregation so he is bound to say "The problem lay with the "Finnish Study", not with our designs"

And you're not bound to be against cycle lanes and tracks?

Did you even read the quote from Paul Gannon?

And since you seem to have a knack to conflate issues, why stop now, what about the studies showing that spending on cycling infrastructure has returns somewhere between 3-to-1 and 9-to-1 if memory serves?

Anyway, rate of cycling in Finland is something like 5 times higher than UK, which IMO is even more impressive when you consider 3 months of snow. (There was another detail that makes the figure even more impressive but it escapes me.) Finland has significant cycling infrastructure separated from cars. It is clear to me that cycling infrastructure is necessary, though not sufficient, condition for number of people cycling, and the number of studies saying the same thing strongly supports that. And yes, I know it'll never satisfy your demands for conclusive proof (though I find it oddly convenient you're also against spending any money to actually build such infrastructure which could be studied to your satisfaction.)

I'll see your numbers later, but the road traffic casualty statistics in general are very different in Finland which naturally reflects to cycling as well.

Do you have any studies proving cycling in Finland is abnormally unsafe because of the cycling infrastructure? Do you have any studies besides the bunked Helsinki report even suggesting that?

 

[Origamist]

I think we are talking about rules of thumb and principles here, rather than hard and fast rules. Every situation has to be assessed to try to minimize the risks as much as possible.

Indeed - the issue here is that people calibrate their risk thermostats differently. For some, riding slowly and being vigilant in the 3ft passing range is preferable to riding 5ft out (due to the potential problems this can create with oncoming and following traffic). Others, might not consider the danger posed by car doors as much of a threat (I suspect you could cycle for years and never get hit, passing 10000s of cars in the process), others might back their cat-like reflexes, others might not even give the door zone a second thought. For some, the grief that you can receive (be it verbal or physical bullying) can be enough to inhibit people from riding a good distance from the door zone, even though they know it can be dangerous to cycle too close to parked/stationary vehicles (not only because of doors, but because pedestrians can be obscured as well).

It's tempting to be dogmatic on the issue, but real world situations with on-the-fly risk assessments can make things less clear cut.

 

[MrHappyCyclist]

It's tempting to be dogmatic on the issue, but real world situations with on-the-fly risk assessments can make things less clear cut.

True. We've evolved to use bounded rationality anyway because if you spend too long calculating the best direction to run in, you've already been eaten before you make a decision.

 

[Angelfishsolo]

True. We've evolved to use bounded rationality anyway because if you spend too long calculating the best direction to run in, you've already been eaten before you make a decision.

I believe they now call it dynamic risk assessment

 

[Origamist]

True. We've evolved to use bounded rationality anyway because if you spend too long calculating the best direction to run in, you've already been eaten before you make a decision.

I've never come across anyone who has used the term "bounded rationality" on a commuting forum! FWIW, my cycling modus operandi is very much of the "satisficing" kind...

 

[Red Light]

And you're not bound to be against cycle lanes and tracks?

No. If there is evidence they work at significantly increasing safety or attracting people to cycling I would support them. But so far I have found little to no evidence they do either. They do cost a lot of money though at about £1m/mile.

Did you even read the quote from Paul Gannon?

Yes. And? Its just a diatribe full of aspersions and assertions with no evidence base. Paul, like David, is committed to segregation being the solution.

And since you seem to have a knack to conflate issues, why stop now, what about the studies showing that spending on cycling infrastructure has returns somewhere between 3-to-1 and 9-to-1 if memory serves?

Link?

Anyway, rate of cycling in Finland is something like 5 times higher than UK, which IMO is even more impressive when you consider 3 months of snow. (There was another detail that makes the figure even more impressive but it escapes me.) Finland has significant cycling infrastructure separated from cars. It is clear to me that cycling infrastructure is necessary, though not sufficient, condition for number of people cycling, and the number of studies saying the same thing strongly supports that. And yes, I know it'll never satisfy your demands for conclusive proof (though I find it oddly convenient you're also against spending any money to actually build such infrastructure which could be studied to your satisfaction.)

That is just your conjecture. Perhaps you can cite some of those studies you talk about. The reason I don't want to spend money building that infrastructure to be studied is because its already been done in lots of places and cycling either stayed static or fell.

The DfT carried out a ten year study in 8 towns and cities to "measure and evaluate the effect of providing a continuous cycle route or network, particularly on cyclists' safety and cycle use" (Traffic Advisory Leaflet 5/95). It found

"Constructing safe routes did not of itself encourage those who own cycles - but do not currently us them - to start cycling."

"In Exeter, Kempston, Stockton, and parts of Nottingham, the introduction of cycle routes led to a fall in the number of people who considered cycling to be dangerous. There was no correlation between the perception of the danger of cycling and the changes in observed cycle flows. Overall there was no change in the number of cyclist casualties in the towns studied."

Dublin built a 320km commuter cycling network and saw a 15% drop in commuter cycling and a 40% drop in cycling to school. The Netherlands saw no cycling increase in return for spending ~ $1Bn on cycle tracks, neither did Germany. How many more of these "experiments" do we need to spend money on?

Do you have any studies proving cycling in Finland is abnormally unsafe because of the cycling infrastructure? Do you have any studies besides the bunked Helsinki report even suggesting that?

Cyclists cycling against the traffic flow on a two way cycle lane have a 12.4x (Sweden), 10x (Finland) increased collision risk compared to on the road and 3.4x (Sweden) and 4x (Denmark) higher risk in the with traffic direction.

Rasanen M, Summala H, Pasanen E, The safety effect of sight obstacles and road markings at bicycle crossings Traffic Engineering and Control, 39(2), 98-102, 1998


Rasanen M, Summala H, Attention and expectation problems in bicycle-car collisions: an in-depth study. Accid Anal. Prev.30(5):657-66. 1998

 

[Tommi]

No. If there is evidence they work at significantly increasing safety or attracting people to cycling I would support them. But so far I have found little to no evidence they do either. They do cost a lot of money though at about £1m/mile.

That is just your conjecture. Perhaps you can cite some of those studies you talk about. The reason I don't want to spend money building that infrastructure to be studied is because its already been done in lots of places and cycling either stayed static or fell.

See my response here.

The DfT carried out a ten year study in 8 towns and cities to "measure and evaluate the effect of providing a continuous cycle route or network, particularly on cyclists' safety and cycle use" (Traffic Advisory Leaflet 5/95). It found

"Constructing safe routes did not of itself encourage those who own cycles - but do not currently us them - to start cycling."

"In Exeter, Kempston, Stockton, and parts of Nottingham, the introduction of cycle routes led to a fall in the number of people who considered cycling to be dangerous. There was no correlation between the perception of the danger of cycling and the changes in observed cycle flows. Overall there was no change in the number of cyclist casualties in the towns studied."

TAL 5/95 looks like a summary of summaries. Would you mind showing the underlying reports? Strangely enough the abstracts I looked at had this to say about Exeter:


"There has been an increase in numbers of cyclists, and the majority consider it to be safer than other routes."

and Nottingham:

"Nationally there was a general decline in cycling of 15 per cent whereas in Nottingham as a whole the figure was 8.7 per cent. On the route, comparing 1985 with 1989, no fall in cycle travel occurred, and in 1990 there were notable increases recorded in Wollaton and Castle Boulevard, the latest areas to benefit from the route implementation."


and


"cyclist casualties fell"

Dublin built a 320km commuter cycling network and saw a 15% drop in commuter cycling and a 40% drop in cycling to school. The Netherlands saw no cycling increase in return for spending ~ $1Bn on cycle tracks, neither did Germany. How many more of these "experiments" do we need to spend money on?

Link?

Looking at the Dublin Inner Canal Cordon Counts 1988-2003 figures I see (chart):

1. Trend from 1988 to 1996: -300 trips/year
2. Trend from 1997 to 2003: -100 trips/year (from commencement of cycle network)
3. Trend from 1988 to 2003: -217 trips/year

So given the overall trend in cycling was already in decrease it seems to me the cycle network had very significant positive influence on cycling.

Cyclists cycling against the traffic flow on a two way cycle lane have a 12.4x (Sweden), 10x (Finland) increased collision risk compared to on the road and 3.4x (Sweden) and 4x (Denmark) higher risk in the with traffic direction.

Rasanen M, Summala H, Pasanen E, The safety effect of sight obstacles and road markings at bicycle crossings Traffic Engineering and Control, 39(2), 98-102, 1998


Rasanen M, Summala H, Attention and expectation problems in bicycle-car collisions: an in-depth study. Accid Anal. Prev.30(5):657-66. 1998

Links?

Then again, those are even older studies used as the basis for the Helsinki study. I really meant do you have something more recent? Because best I can tell the findings of that study have never been repeated, in Finland or elsewhere, which doesn't really give much credibility to the claims. In the meantime Finland (to my knowledge) has continued building this incredible lethal cycling infrastructure for over a decade, so surely cycling injury rates would've grown totally out of proportion by now and you have evidence to prove it?

(As this has little to do with commuting, continue in the other forum?)