Archive for the ‘Traffic’ Category

The Lessons of 2013


Every week I scan the abstracts of about 25 new papers published in peer reviewed journals and by universities. Sometimes I have access to complete papers.

They are all relevant to cycling and I try to stick to the one that have some basis in, or relevance to, science. Considering I read only those written in English, ones that cross my radar and ones that I have any hope of understanding, clearly there’s a lot out there that I miss. Nevertheless, the pickings are rich and diverse.

While I tweet nearly everything I find (@cyclingscience1), here’s a summary of  a little of what I’ve learned this year from those thousands of diligent researchers who continue to add to our understanding of cycling.

I don’t necessarily agree with any of them.

• Yoga stresses the heart and respiratory system less than cycling
• The weaves of skinsuit materials affect your aerodynamics
• Bike reviews criticising comfort are largely untrustworthy
• Regenerative braking for e-bikes is going to blossom
• Cycling in London is either more dangerous or the safety models were wrong
• The Mayor of London is more worried about commerce than road safety
• Mountain bikers suffer the worst injuries in the first third of an endurance race
• French riders in the Tour de France live longer than mere French mortals
• Traffic calming and separate cycle paths make cycling safer in Netherlands
• Medics worldwide believe that bicycle helmets are fantastic
• The health benefits to US society of cycling outweigh the costs
• Caffeine definitely helps if you drink it, but not as a mouth rinse
• Cars don’t pass helmeted cyclists any closer than they pass bare-headed riders
• Steer by wire is on its way for e-bikes
• Support for, and research into, safety in numbers is growing
• Male cyclists have bigger thighs than triathletes
• The secrets of bicycle stability and steering remain enigmatic
• The best time to ride along Oxford Street in London is 10:07 on 25th DecemberOxford St cycling 25 Dec

To stay ahead of the bunch in 2014, buy a copy of Cycling Science and follow the tweets @cyclingscience1

Listen up!


traffic bicycleSshhh! Cycling’s way down the list of noise polluters. A well-maintained bike on a smooth surface can be near-silent (assuming the rider isn’t wearing chain mail, playing a bugle or both). The peacefulness is one of its pleasures.

So that makes a bicycle a relatively good platform for collecting other sounds on the move. What you do with those noises is up to you and different scientists are doing surprising things.

There’s a team in Austria that’s been eavesdropping on a rider as she pedals around the town of Graz. She knew about it. Before she started she phoned the lab and kept the call connected. The researchers were able to hear all the sounds around her wherever she cycled.

Then they analysed the audible clues and, like sound detectives with their ears to the ground, they succeeded in working out her route just from the noises they heard through her phone. It’s an impressive result.

It’s not clear from this experiment who had the most fun but it does show that even if you doubt the existance of Big Brother (he does exist), it seems that he doesn’t need to watch you to find out where you are. All he has to do is listen and he’s got you located.

The research paper will download when you click here.

Elsewhere, three unfamous (as yet) Belgians have been cycling round cities capturing the traffic noise as they ride. At the same time they’ve been sampling the air, not just through their own mouths and noses but also through chemical sensors.

They made 200 trips and then calculated that there is a relationship between traffic noise and the level of carbon particles that pollute the air. This shouldn’t be very surprising because it stands to reason that the more traffic there is, the noiser it is and the greater the quantity of pollutants they are pumping into the atmosphere.

Here’s the clever thing about the research. Lots of people want to know how dirty the air is in our city streets at different times of day and in different weather conditions. The general aim is to keep the air cleaner somehow or other and thus improve everybody’s health. The problem, though, is that air quality monitoring equipment isn’t cheap.

By showing that noise levels are a reliable indicator of air pollution levels, the Belgian team says that audio recordings captured by street-level microphones can reveal the truth just as effectvely as air quality sensors. And microphones are much, much cheaper.

How ironic that the toxic emissions from motor vehicles will be more easily monitored because of an experiment by cyclists.

The abstract of the research can be seen here.

Mind the gap – how close do cars come?


How much room does a driver give a cyclist when overtaking? What do you do as a cyclist when a car is passing you? How straight is the line you ride as vehicles pass you by? A group of scientists in Taiwan built a special bike to answer these questions and more.

Bicycle instrumented for rider/driver behaviour

All the on-board kit

It was instrumented to record lateral distance from the passing motorists, wheel angle and speed control. That’s a lot of special kit to add to a bicycle on city streets. It includes an ultrasonic sensor, camera, a variable resistor in the headset and a solid state compass, gyroscope and accelerometer. OK, it costs less than a CF disc wheel but it’s a lot of value to expose to potentially hazardous situations.

Well, as with the vast majority of urban rides, nothing went wrong and the data were analysed. Thirty-four riders were overtaken a total of 1,380 times. The equipment revealed that

• motorbikes passed more closely to the bicycle than cars and trucks did.

• cyclists couldn’t keep such a straight line when buses overtook

• vehicles passing slowly led to more cautious but less stable riding

• a solid white line, like for a bike lane, increases the distance between passing vehicles and bicycles
• motorists pass closer to men than women.
This last point confirms the 2007 findings of Dr Ian Walker of Bath University and some subsequent US research.
However, what’s not clear from the latest research is how much the beaviour of the riders and the drivers was influenced by the test itself. The riders would’ve at least been aware of the equipment of the bike and so may have ridden differently from normal.
Likewise the motorists could’ve seen the oddly-equipped bicycle and so changed from their normal steering pattern.
Nevertheless, I like this kind of research because it attempts to quantify experiences familiar to every cyclist and so it helps by converting anecdotes into evidence that may be used to improve road safety.


The use of a quasi-naturalistic riding method to investigate bicyclists’ behaviors when motorists pass, published in  Accident Analysis & Prevention, available online 29 March 2013, by Kai-Hsiang Chuang, Chun-Chia Hsu, Ching-Huei Lai, Ji-Liang Doon and Ming-Chang Jeng

Two new technologies – Number 2

I prefer the one on the left but spend too long, too often, looking at the one on the right

I prefer the one on the left but spend too long, too often, looking at the one on the right

OK, so you were less than overwhelmed by my shock revelations that Sturmey Archer might just perhaps possibly may be about to produce a 16 speed hub gear for bicycles. Jeez, some people are never satisfied.

How about this then? This will turn your world upside down. If it doesn’t then don’t blame me because the problem lies deep in your psyche and you’re not the kind of person I want visiting my blog anyway.

The big technology revelation today is, wait for it, something that means you won’t have to hang around at traffic signals waiting for them to go from red to green while you’re standing patiently astride your bicycle for ages and ages. There, quite a shocker, I think you’ll agree. What follows is the explanation of the problem and the latest solution.

Too many traffic signals have induction loops ahead of them, cut into the road. They detect the metal in cars, lorries, buses and even motorbikes with ease, and pass the data to the control box. When the system inside the control box decides the traffic’s been queuing long enough, it gives them the green light.

But induction loops are utter rubbish at detecting cyclists and bicycles. The problem is that most cyclists and many parts of bicycles are not made out of metal so the induction loops don’t spot us when we arrive. Subsequently, the control box doesn’t know we’re there and, unless another vehicle pulls up, it will never change the signal to green and we’ll wait. And wait. And wait until our patience snaps and we ride through a red light, get spotted by a saintly motorist who then writes to their local newspaper/councillors/police to condemn every single cyclist in the world as a monster the likes of which hasn’t been seen riding on our planet since Attila the Hun.

Of course, we all know that it’s all our fault, we cyclists should stop whinging and be grateful that we’re allowed on the roads anyway.  The obvious solution is that we should all start wearing chain mail and suits of armour containing sufficient metal to be seen by the induction loops.

However, some of us think that there should be a better way for traffic signals to know that cyclists are waiting for a green light. Fortunately, people at Sensys Networks agree. They make their money from traffic technology and they’ve seen how roads agencies might like to buy products that will assist the growing number of cyclists.

Sensys MicroRadar

Seen this on the road? Let me know – and ask your local traffic engineers to install them wherever there’s traffic signals

They’ve invented something branded as MicroRadar. It’s a little box that can be sunk into the road surface. It has a battery so it doesn’t need to be connected to any power supply. It communicates wirelessly with the control box. And, as its name suggests, it uses radar – to detect cyclists. Yippeee!

The diligent among you, by which I mean all of the most beautiful and clever readers of this blog, will already have searched for Sensys and MicroRadar and discovered that, quite unusually, this blog is two years behind the curve. I acknowledge that Sensys released the product in 2011. So why am I devoting valuable pixels to it now?

Because I have discovered that the first such unit in the UK is being trialled. Somewhere out there, on a road on the British mainland, cyclists are being detected by radar and getting a green light on the traffic signals when they might otherwise have to wait for an annoyingly long time.

Talking of being annoying, I’m going to have to be annoyingly reticent about its exact location. I know in which urban conurbation it is sited but I would be breaching confidentiality if I was any more specific. I wasn’t told not to reveal it but the information came to me without any knowledge I’d be writing about it here. See? I do have some morals. Not many, for sure, but I really don’t want to end up as aggregate under some new motorway widening scheme so I shan’t push my luck any further.

If you can be as patient as a cyclist waiting for a green light, the location will probably be released on 16th April 2013 and, if I remember, I’ll post it on the blog. Until then, if you want to know exactly where it is, you’ll have to study the road surface every time you approach some traffic signals.

Of course, if you do spot it and happen to post the info on the web before 16th April, please let me know so that I can republish it without fear of being accused of breaking my informant’s trust.

In the meantime, in case my informant is unhappy with this blog entry and for self-protection reasons only, I shall now put on my chain mail and suit of armour.

More contenders for 2012 Cycling Science awards


Here’s a couple of new nominations for the 2012 Cycling Science award. If you would like to suggest others, please use the reply form at the bottom of this page.

Out for the count

City planners need the right information to make the best decisions for encouraging cycling. Unfortunately the best information isn’t always available so they compromise and try to extract it from other sources.

For example, they should use accurate traffic counts when assesing the need for road design changes and the construction of better facilities for cycling, either cycle lanes or separated cycle paths.

The trouble is, they sometimes rely on those induction loops embedded in the asphalt and that are often there as part of the traffic signal system. They believe they detect every wheel that crosses them. They are so, so wrong.

While it’s common for the loops to ignore cyclists altogether, it seems from research at Ohio State University that they can’t always detect the lumps of metal that are cars and trucks.

Some of the induction loop counters were wrong by a massive 52%. Such inaccurate data must never be used in designing cycling facilities on or adjacent to the highway.

Head case

There are three things that careful researchers avoid:

1. Entering the febrile arena of discussion about bicycle helmets

2. Questioning head on accepted wisdom, such as that which evolves from Cochrane reviews

3. Taking the time to correct the mistakes made by others.

So three cheers to Rune Elvik at the Institute of Transport Economics in Norway and editor of Accident Analysis and Prevention.

He’s done all three in a dense little paper, which will infurate the pro-helmet lobby because one of its conclusions is that “no overall effect of bicycle helmets could be found when injuries to head, face or neck are considered as a whole.