Segregated lanes? Road safety improvement? More Home Zones? Traffic reduction schemes?
No - it's more tube strikes.
Friday, September 3, 2010
Transmission Knackered
Shifting on my mountain bike failed. Thinking it was the inner cable about to break, I replaced that, but noticed it was actually the outer gear cable which had worn through near the rear mech. So I replaced that. I knew the chain was in need of replacement, so put a new one on and cleaned up the cassette and chainrings. The new chain wouldn't shift properly and skipped over the smaller rear sprockets. So I need a new cassette, rear mech and likely chainset as well.
I think, because I mainly ride the bike fast on-road, I spend a lot of time on the small sprockets and wear them out. I guess this is what you get when you use the wrong tool for the job! So I figure I might be better off either getting a trekking chainset (28/38/48) to replace the mountain chainset (22/32/44), and/or a road cassette (11-23 or 11-25) so I get a better spread of wear over the cassette. But of course I'll then have a bike that's less use off-road, although in practice I almost never use the lowest ratios.
I think, because I mainly ride the bike fast on-road, I spend a lot of time on the small sprockets and wear them out. I guess this is what you get when you use the wrong tool for the job! So I figure I might be better off either getting a trekking chainset (28/38/48) to replace the mountain chainset (22/32/44), and/or a road cassette (11-23 or 11-25) so I get a better spread of wear over the cassette. But of course I'll then have a bike that's less use off-road, although in practice I almost never use the lowest ratios.
CSH #7
A lovely ride in along CSH#7 today. Another sunny but temperate day, and no problems with cars parked in the cycle lane, or vehicle encroachment into it, for the most part, except for a few buses. Of course this is still summer and the kids aren't back at school yet. Next week, I bet, it'll be a different story. More congestion will mean more drivers (and cyclists) doing stupid things.
For the first time I saw the treatment at the Stockwell Gyratory. TfL have at least done something. There is a 'middle lane' you have to get into, which is protected in part by an island that segregates it from the main traffic lane. So it's better than it used to be. But you still need to drift across the left-turning traffic to get to the 'middle lane', which is a very hazardous manoeuvre (hate spelling that word).
The downsides are the same as they've always been though. At traffic lights and junctions, there are hazards aplenty, mainly from left-turning vehicles. Motorcycles are somewhat of a problem also, because they get to the front of the junction in amongst the bikes. There are sections where you have to mix it with fairly fast-moving traffic. You're never segregated from the traffic except in the bus lanes, and they don't operate 24/7 in all cases. Which I've never understood. If there's congestion, you need the bus lane to speed up the bus journey. If there isn't congestion, there's no particular need for other motor vehicles to have an extra lane. Limiting the hours endangers cyclists, may slow buses, and for the most part doesn't improve motor journey times.
For the first time I saw the treatment at the Stockwell Gyratory. TfL have at least done something. There is a 'middle lane' you have to get into, which is protected in part by an island that segregates it from the main traffic lane. So it's better than it used to be. But you still need to drift across the left-turning traffic to get to the 'middle lane', which is a very hazardous manoeuvre (hate spelling that word).
The downsides are the same as they've always been though. At traffic lights and junctions, there are hazards aplenty, mainly from left-turning vehicles. Motorcycles are somewhat of a problem also, because they get to the front of the junction in amongst the bikes. There are sections where you have to mix it with fairly fast-moving traffic. You're never segregated from the traffic except in the bus lanes, and they don't operate 24/7 in all cases. Which I've never understood. If there's congestion, you need the bus lane to speed up the bus journey. If there isn't congestion, there's no particular need for other motor vehicles to have an extra lane. Limiting the hours endangers cyclists, may slow buses, and for the most part doesn't improve motor journey times.
Anti Speed Camera Arguments - #2 - Distraction
Cast your mind back, dear reader, way back to yesterday. You'll recall I'm trying to debunk the anti-speed camera arguments put forward by 'Safe Speed'. I started by addressing the supposed correlation between road death trends and the introduction of speed cameras.
Today I'll look at the idea that speed cameras distract drivers. What case do Safe Speed make?
Today I'll look at the idea that speed cameras distract drivers. What case do Safe Speed make?
"Accidents happen when people make mistakes. About 75% of those mistakes are carelessness or inattention."
Depends what you mean by 'accident'. Most 'accidents' are not due to factors outside the control of drivers, and could and should be avoided. Where do they get 75% from? In terms of inattention, 2003 figures attribute 'driver/rider distracted as a factor in 5.5% of accidents. Does 'Going too fast for circumstances' count as carelessness? What about 'Vision Obscured' - if your vision is obscured you should expect the unexpected and proceed carefully, right? You'll notice I give proper sources and citations for my data. That's because I'm a scientist and I don't expect people to take figures on trust. Unlike 'Safe Speed'.
"About 5% of those mistakes involve excessive speed."
Not according to my previously cited government figures. They say 'Going too fast for circumstances' is a factor in 8.4% of crashes and 'Suspected contravention of statutory speed limit' is a factor in 2.2%. Of course, Government stats are only based on STATS19 forms compiled by the police. Maybe Safe Speed have been able to find a more authoritative source, or do their own analysis of thousands of crashes?
Bear in mind that almost all crashes are less severe and many can be avoided if drivers are going slower. The slower you go the more time you have to react, and the less severe the impact - that's because of Newton's laws (science again you see). Also, the amount of time the police have to analyse crashes is very limited. Many people lie about or at least underestimate how fast they were driving after a crash, and unless the police can gather any evidence to the contrary, excessive speed may not be recorded as a cause. Therefore it seems likely that there is under-reporting of speed as a factor in crashes.
"speed cameras ... alter the things that drivers pay attention to. Too many drivers now spend far too much time considering ... speed limit compliance and the risk of enforcement. Sometimes ... they are spending precious milliseconds worrying about numerical speed while an unseen dangerous situation is developing ahead."
Sorry, but this is a stretch. Driving is always a multitasking activity. You need to systematically scan the road ahead and to the side, your mirrors and your instrument panel on a continuous basis, and increase or reduce your speed according to hazards that you observe. Some people, incredibly, can listen to the radio as well, or conduct a conversation with a passenger! You need to take notice of road signs and comply with them, You need to plan manoeuvres. It's essential to be setting your speed correctly. If you cannot monitor and control your speed whilst driving, you probably shouldn't be driving. Are we saying that drivers who are incapable of doing that would be safer if they worried less about their speed? Are they in fact capable of setting their speed correctly without the guidance of speed limits or the threat of enforcement?
Now, I'm not going to say that speed cameras are never a distraction. They are. But the question is whether the momentary distraction of seeing a speed camera and checking your speed represents a greater danger than allowing higher average speeds (recall from my citation yesterday that cameras do lower average speeds).
Let's look at some other factors that may mitigate the distraction.
1. Most cameras are sited on busy roads. What tends to happen most of the time is you get a moving line of traffic, and the line moves at the speed of the slowest vehicle. That speed is controlled by the camera, so in actual fact drivers don't have to worry about their speed.
2. Many journeys are along familiar roads. Therefore, drivers know both the speed limits and the location of cameras, so they are less likely to be distracted by them as they are on unfamiliar roads.
Thursday, September 2, 2010
Anti Speed Camera Arguments - #1 Deaths and Camera Convictions
You might think, given the current Government's stance against speed cameras, that there was a large body of evidence that they don't work. Curiously enough, I've not been able to find any evidence to that effect from an authoritative road safety source. I'd love for someone to point me at anything relevant.
So I took a look at 'Safe Speed', which is an anti-camera website that has got a fair amount of press coverage, in the hope that there was a good, properly-argued and properly-sourced case.
I wasn't convinced. So I thought I would try to deconstruct their arguments. I'll do this in a series of posts so you don't get too bored. Their arguments can be viewed at http://www.safespeed.org.uk/effects.html .
#1 Deaths and Camera Convictions.
In this section, Safe Speed try to argue that the decline in road fatalities has flatlined, so that the long-term trend in reduction of road fatalities has ceased. They argue that this is correlated with the increased use of speed cameras. There would appear to be a correlation based on the graph they present, but they've cherry-picked their reporting period - it ends in 2002. Since 2002, fatalities have declined from 3127 to 2538 in 2008 (source).
Safe Speed argue that 'if cameras saved lives' there would have been a decline to below 1500 deaths by 2002. However, they do not state their sources, assumptions or methodology, so it's impossible to know how they've arrived at this figure other than by drawing a more-or-less straight line. If only statistical analysis were that simple.
It's convenient that I have the figures for 2008, because that fills in the gap in their analysis. They give the following analysis:
Period %Decline in Road Deaths (that is, the end total as a percentage of the starting total)
1978-1982 86.8
1982-1988 85.1
1988-1992 83.7
1998-2002 100.3
But between 2002 and 2008, we have a decline to 81.2% of the 2002 total. What does that work out at per year? 2002-2008 gives an average annual 3.13% improvement. Between 1982 and 1998, there was an average annual 3.03% improvement. Now bear in mind that the period 1982 - 1998 included two recessions, and recessions improve road safety. I am not trying to prove a causal link, but I am pointing out that the Safe Speed's graphs don't extrapolate. It's not possible to conclude from any of these statistics what the effect of speed cameras is. There are many factors that affect crash rates: increases in car ownership, increases in distances driven, a thriving economy, social factors, demographics, increase in foreign drivers, improvements in vehicle safety, highway engineering (including lower speed limits and speed cameras), lower numbers of traffic police, increases in mobile phone use, changes in public attitudes, and so on. Safe Speed's argument is that because they cannot explain the departure from a linear trend with a single factor, it must be down to speed cameras.
Safe Speed's assumption of a linear decline in death rates is clearly flawed. According to them, if speed cameras saved lives then by linear extrapolation there would be no road deaths by 2010. It seems obvious that a linear extrapolation is both statistically invalid and also isn't realistic: speeding continues despite the presence of speed cameras, and there are other factors besides speed that cause road deaths.
According to Devon and Cornwall Safety Camera Partnership, "In the first two years of [camera] operation the number of injury collisions in this area has fallen by 27% and the number of people killed or seriously injured has reduced by 7%. However on those roads where cameras are used there has been a 44% reduction in crashes and a 17% reduction in casualties. Also the average speed of vehicles on the roads has reduced by 12% and the percentage of drivers exceeding the speed limit has been reduced from 64% to 33%." It is very difficult to square that with Safe Speed's world view.
In conclusion, the arguments put forward by Safe Speed to suggest a causal link between the use of speed cameras and an end to the decline in UK road deaths are selective in their use of evidence and use very questionable methodology and statistical techniques. In other words, it is not scientific.
Next, I'll be looking at Safe Speed's analysis of how speed cameras affect drivers.
So I took a look at 'Safe Speed', which is an anti-camera website that has got a fair amount of press coverage, in the hope that there was a good, properly-argued and properly-sourced case.
I wasn't convinced. So I thought I would try to deconstruct their arguments. I'll do this in a series of posts so you don't get too bored. Their arguments can be viewed at http://www.safespeed.org.uk/effects.html .
#1 Deaths and Camera Convictions.
In this section, Safe Speed try to argue that the decline in road fatalities has flatlined, so that the long-term trend in reduction of road fatalities has ceased. They argue that this is correlated with the increased use of speed cameras. There would appear to be a correlation based on the graph they present, but they've cherry-picked their reporting period - it ends in 2002. Since 2002, fatalities have declined from 3127 to 2538 in 2008 (source).
Safe Speed argue that 'if cameras saved lives' there would have been a decline to below 1500 deaths by 2002. However, they do not state their sources, assumptions or methodology, so it's impossible to know how they've arrived at this figure other than by drawing a more-or-less straight line. If only statistical analysis were that simple.
It's convenient that I have the figures for 2008, because that fills in the gap in their analysis. They give the following analysis:
Period %Decline in Road Deaths (that is, the end total as a percentage of the starting total)
1978-1982 86.8
1982-1988 85.1
1988-1992 83.7
1998-2002 100.3
But between 2002 and 2008, we have a decline to 81.2% of the 2002 total. What does that work out at per year? 2002-2008 gives an average annual 3.13% improvement. Between 1982 and 1998, there was an average annual 3.03% improvement. Now bear in mind that the period 1982 - 1998 included two recessions, and recessions improve road safety. I am not trying to prove a causal link, but I am pointing out that the Safe Speed's graphs don't extrapolate. It's not possible to conclude from any of these statistics what the effect of speed cameras is. There are many factors that affect crash rates: increases in car ownership, increases in distances driven, a thriving economy, social factors, demographics, increase in foreign drivers, improvements in vehicle safety, highway engineering (including lower speed limits and speed cameras), lower numbers of traffic police, increases in mobile phone use, changes in public attitudes, and so on. Safe Speed's argument is that because they cannot explain the departure from a linear trend with a single factor, it must be down to speed cameras.
Safe Speed's assumption of a linear decline in death rates is clearly flawed. According to them, if speed cameras saved lives then by linear extrapolation there would be no road deaths by 2010. It seems obvious that a linear extrapolation is both statistically invalid and also isn't realistic: speeding continues despite the presence of speed cameras, and there are other factors besides speed that cause road deaths.
According to Devon and Cornwall Safety Camera Partnership, "In the first two years of [camera] operation the number of injury collisions in this area has fallen by 27% and the number of people killed or seriously injured has reduced by 7%. However on those roads where cameras are used there has been a 44% reduction in crashes and a 17% reduction in casualties. Also the average speed of vehicles on the roads has reduced by 12% and the percentage of drivers exceeding the speed limit has been reduced from 64% to 33%." It is very difficult to square that with Safe Speed's world view.
In conclusion, the arguments put forward by Safe Speed to suggest a causal link between the use of speed cameras and an end to the decline in UK road deaths are selective in their use of evidence and use very questionable methodology and statistical techniques. In other words, it is not scientific.
Next, I'll be looking at Safe Speed's analysis of how speed cameras affect drivers.
Cycle Hire Update
The perfect day. Not too cold, not too hot, but sunny, and the kids aren't back at school yet so traffic still at summer levels. Cycling in, I saw hire bikes being moved. In Black Prince Road, I saw that the docking station was completely empty, and there was a van with a trailer loaded with bikes. My guess is that this docking station is a popular start-point for people riding to work in the West End and City - it's a very short ride - and they were about to 'restock'.
As I rode along Tufton Street, I saw another van with hire bikes, and a group of bikes on the pavement. I'd noticed a few weeks back that the Smith Square docking station is full in the morning, and I've read elsewhere about areas where all the docking points saturate in the morning. Have they created a temporary drop-off point on Tufton Street?
It rather looks like the scheme is beginning to be a victim of its own success. The question is, can this success be scaled up? Clearly, more capacity is needed. The problem may be financial. It would be a great shame if the scheme partly fails because users can't rely on getting a bike when they need one.
As I rode along Tufton Street, I saw another van with hire bikes, and a group of bikes on the pavement. I'd noticed a few weeks back that the Smith Square docking station is full in the morning, and I've read elsewhere about areas where all the docking points saturate in the morning. Have they created a temporary drop-off point on Tufton Street?
It rather looks like the scheme is beginning to be a victim of its own success. The question is, can this success be scaled up? Clearly, more capacity is needed. The problem may be financial. It would be a great shame if the scheme partly fails because users can't rely on getting a bike when they need one.
Wednesday, September 1, 2010
Oona King - Human Rights and Parking Fines
Oona King jumps on the anti-war-against-the-motorist bandwagon in the Standard today, bleating about the unfairness and inflexibility of parking fines. Now, there are cases of injustice and unfairness, as there are in all areas of law enforcement. But the consequences are usually a relatively small fine. This hardly equates to a gross infringement of human rights, as Oona's article seems to imply. And most motorists can afford it. If they couldn't, there wouldn't be such widespread infringement of parking regulations. If all motorists could be trusted to park considerately, we wouldn't need any parking enforcement. As for inflexibility, this is of necessity. Google 'parking fine', and you'll find a whole industry dedicated to helping motorists wriggle out of their offences.
"Some people are always going to need to drive", Oona gushes, "whether it's the plumber who needs to carry tools or the disabled person with their specially adapted vehicle. These people should have parking facilities and a parking regime that means they can go about their business without fearing a fine for being a couple of minutes late."
In case you hadn't noticed, Oona, there's a blue badge scheme for disabled people. And able-bodied people for that matter, so widespread is the abuse of it. Most plumbers and van drivers can tell the time and can understand parking restrictions. Getting the odd ticket is an occupational hazard. Ain't that terrible? What's your solution, Oona? Create more loopholes and overload the parking appeals process with frivolous cases? Reduce fines and impoverish councils still further? Or just abolish parking restrictions altogether? You don't know do you? You've not thought this through, have you? This is lowest-common-denominator politics, and Oona King has just gone down in my estimation.
What Oona doesn't seem to understand is, the cheaper and easier you make driving, the more people will tend to drive. The reason there is little private motoring in central London is parking is difficult and expensive, and you have to pay the congestion charge. If you make it cheaper and easier for people to take the car, there'll be more congestion. Your plumber will lose more earnings than he's paying in parking fines, because he'll be stuck in traffic more of the time. As for Oona's anecdote about a woman whose car was clamped while her father was having a heart attack - do you want more ambulances stuck in traffic?
"Some people are always going to need to drive", Oona gushes, "whether it's the plumber who needs to carry tools or the disabled person with their specially adapted vehicle. These people should have parking facilities and a parking regime that means they can go about their business without fearing a fine for being a couple of minutes late."
In case you hadn't noticed, Oona, there's a blue badge scheme for disabled people. And able-bodied people for that matter, so widespread is the abuse of it. Most plumbers and van drivers can tell the time and can understand parking restrictions. Getting the odd ticket is an occupational hazard. Ain't that terrible? What's your solution, Oona? Create more loopholes and overload the parking appeals process with frivolous cases? Reduce fines and impoverish councils still further? Or just abolish parking restrictions altogether? You don't know do you? You've not thought this through, have you? This is lowest-common-denominator politics, and Oona King has just gone down in my estimation.
What Oona doesn't seem to understand is, the cheaper and easier you make driving, the more people will tend to drive. The reason there is little private motoring in central London is parking is difficult and expensive, and you have to pay the congestion charge. If you make it cheaper and easier for people to take the car, there'll be more congestion. Your plumber will lose more earnings than he's paying in parking fines, because he'll be stuck in traffic more of the time. As for Oona's anecdote about a woman whose car was clamped while her father was having a heart attack - do you want more ambulances stuck in traffic?
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