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Enforcing 3-foot passing law with the help of science

Police in Tennessee are using a new device to measure whether motorists are adhering to safe passing distances when overtaking cyclists.

The device, shown off by police on National Bike to Work Day, can measure how close a car is to a bike.

One Chattanooga local, Pearl Pangkey told  WRCBtv there's still a long way to go.

“I don't think there's enough bike lanes and I think we just have to educate the public,” she said.

“I was going really slow because there was traffic and I was peddling and I hear this really loud engine sound and I turn and there's this big black SUV right beside me. I could have reached out and touched his hood,” she added.

“Where this is a collision between a cyclist and a motorist, the cyclist is almost always going to lose in that collision. They're going to get hurt,” Chattanooga Police Officer Rob Simmons, who created the device, said.

“It's an opinion of an officer that sometimes will hold up in court and sometimes won't because judging distance from a distance is very difficult,” Simmons added.

Together with a Texas-based engineer, Simmons used radar to measure precisely to the inch how close a car is coming to a cyclist.

“[The signal will] bounce off the vehicle and then come back and I'm given a distance in inches of how far away the motorist was when they passed,” he said.

“As cyclists, we need to be predictable to the motorists and the only way to be predictable is to follow the laws that are set up. We are to act like vehicles and we have all the rights and responsibilities as vehicles,” Simmons said.

Drivers who flout the 3 foot rule are subject to a fine.

Last year we reported how painted bike lanes make no difference to the speed and closeness with which drivers pass cyclists, according to a study, but if roads don't have centre-line markings, drivers pass cyclists more slowly.

That's the conclusion of a new study by two academics from the Universities of Leeds and the West of England.

They set out to find out how much difference road markings make to the amount of space drivers give cyclists when passing, and the speed at which they pass in 20mph and 30mph zones.

Stella C. Shackel of the Institute for Transport Studies at the University of Leeds, and John Parkin, Professor of Transport Engineering at the Centre for Transport and Society, University of the West of England published their findings in the paper Influence of road markings, lane widths and driver behaviour on proximity and speed of vehicles overtaking cyclists.

Using a bike equipped with an ultrasonic distance sensor, the authors measured the passing distance of vehicles, and side-facing cameras were used to measure passing speed. Recording each pass allowed the researchers to determine the type of vehicle and so differentiate between cars, light goods vehicles, heavy goods vehicles and so on.

In September last year a law requiring drivers to stay at least three feet away from bicycles when overtaking was passed in California.


The law is designed to take the guesswork out of what a ‘safe’ passing distance is - but politicians say it’s more about creating a visual image for drivers of how far away they should be, than being something police are able to enforce.

The law has long been debated in the state, with earlier versions being vetoed by opposing politicians in 2011 and 2012. The new bill, which has been simplified from earlier incarnations, was sponsored by the city of Los Angeles, which is known for its car-centricity. 

A growing activist base has supported the bill, which was deemed necessary despite a 2010 launched a “Give Me 3″ graphic campaign encouraging drivers to create a safe distance between vehicles and cyclists.

Under the law, if traffic or roadway conditions prevent motorists from giving cyclists 3 feet of clearance, drivers must “slow to a speed that is reasonable and prudent” and only pass when the cyclist will not be endangered.

Fines run to $35 for violations, but this rises to $154 with additional fees. Drivers who collide with cyclists and injure them while violating the law will be subject to a $220 fine.

After an unpromising start, having to be bribed by her parents to learn to ride without stabilisers, Sarah became rather keener on cycling in her university years, and was eventually persuaded to upgrade to proper road cycling by the prospect of a shiny red Italian bike, which she promptly destroyed by trapping a pair of knickers in the rear derailleur. Sarah writes about about cycling every weekend on road.cc.

10 comments

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brucethebruce [36 posts] 2 years ago
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It's usually the second car that will skite past you. No concept of anything past their bonnet.

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BigManLittleHair [45 posts] 2 years ago
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well that's that sorted. $220 for injuring a cyclists. good value some might say, ffs.

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CanAmSteve [253 posts] 2 years ago
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CapriciousZephyr [87 posts] 2 years ago
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Quote:

“As cyclists, we need to be predictable to the motorists and the only way to be predictable is to follow the laws that are set up. We are to act like vehicles and we have all the rights and responsibilities as vehicles,” Simmons said.

I thought everyone needs to proceed in such a way that everyone remains safe if the UNpredictable happens. The above quotation seems to betray a still-accepted, ingrained victim-blaming attitude in society.

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ch [188 posts] 2 years ago
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The description of the California 3-foot law was incomplete. It only applies to situations where passing is allowed (dashed center line) and no other traffic present to prevent a 3-foot gap (e.g., oncoming traffic, traffic in parallel lane). In other situations (e.g. solid center line, other traffic present) cars may legally pass bicycles at any distance they wish. It is notable that some other states do not have this loophole.

The net effect of the law has been that a majority of drivers have become a little more aware of cyclist safety and safe passing. This is a good thing. Unfortunately, for a minority of drivers, suffering from pent up aggression like testosterone supplemented attack dogs shut inside a car for too long without exercise, the sight of physical exertion drives them insane, which combined with the unbearable insult of being morally constrained in showing bicycles who is boss, results in ever closer and more dangerous passing practices - which because of the legal loophole are usually actually legal.

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ConcordeCX [265 posts] 2 years ago
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CapriciousZephyr wrote:
Quote:

“As cyclists, we need to be predictable to the motorists and the only way to be predictable is to follow the laws that are set up. We are to act like vehicles and we have all the rights and responsibilities as vehicles,” Simmons said.

I thought everyone needs to proceed in such a way that everyone remains safe if the UNpredictable happens. The above quotation seems to betray a still-accepted, ingrained victim-blaming attitude in society.

The first part of his first sentence seems reasonable to me. If you cycle (or drive, or walk, or jog, or roller skate) in a way that makes it clear for other road users to see what you're doing and what you're about to do, then barring psychopaths, drunks and just plain ordinary twats you'll probably be ok.

The second part ('the only way ...') is arguable, to say the least.

The second sentence ('act like vehicles') is the basic principle of 'vehicular cycling' and is a good way of making it clear to other road users what you're doing.

Sometimes the victims are to blame. On my ride home this evening I watched one cyclist come out of a junction onto the main road at very high speed, without stopping and without looking, straight in front of me; we didn't collide because I'd seen him coming, guessed what he was about to do, and slowed down. He then went straight through a red light into two busy streams of traffic. How he's survived to adulthood is beyond me, and if he'd been crushed by a truck it would have been his own fault. Still, at least he was predictable.

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Matt eaton [741 posts] 2 years ago
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Demanding that drivers pass with a 3 foot gap is far too simplistic. Imagine you are taking on a climb on an A road with the normal 60 mph limit. You're doing less than 10 mph as you battle up the hill and someone blasts past at 60 mph just 3 feet from your shoulder. That's way too close. I've got no problem with being passed at such speeds provided the gap is sufficient and equally 3 feet is adequate when speeds are lower.

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donnieboy [10 posts] 2 years ago
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220 fine for injuring a cyclist? Potential manslaughter...wow.

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ajft [27 posts] 2 years ago
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"I was peddling..." You'd think that a cycling journal would know the difference between pedal and peddle, but apparently not.

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pete666 [17 posts] 1 year ago
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The 3' distance not being enough room in many circumstances is the point I was going to make. Better than drivers trying to graze one's elbow I suppose?