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How a Combination of Crossroad Angles and Car's A-Pillars Have Created the Perfect Deadly Intersection for Cyclists
The unique features of this Ipley Cross intersection, and your average car design, have proven fatal to those on two wheels
Three people hit by bikes, two of them fatally, over a five-year-span might not sound like much. But any death that would have been preventable with better design is a tragedy. At Ipley Cross in the UK, the intersection of Beaulieu Road and Dibden Bottom has yielded surprisingly consistent car-bicycle impacts, and the last two people to be struck were killed. "Why it that the same collision keeps occurring at this junction?" asked Bez, who writes for cycling magazine Singletrack.
I'll nutshell Bez's description here, but I hope you will click over and read the full article, which goes into much greater detail.
This is an overhead view of the intersection in question. In each of the accidents, the cyclists were traveling south on Beaulieu when they were struck by cars traveling west on Dibden. In each case, it appears neither saw the other until the last moment.
Enter a caption (optional)Why does this keep happening? For the following factors. First off here's the blind spot presented by the A-pillar in the Vauxhall Zafira, a not unusual automobile in Europe, that was involved in the first fatal crash. (Remember that this is in the UK and the driver sits on the right.)
Enter a caption (optional)Here is the blind spot extrapolated onto an overhead view of the intersection.
Enter a caption (optional)Here is how that blind spot tracks, as shown in different colors, as the car approaches the intersection.
Enter a caption (optional)It is possible for a cyclist (represented by aqua blue line in the photo below) to be traveling south at a constant speed and to remain in the driver's blind spot for that entire stretch of road.
Enter a caption (optional)That explains the driver not seeing the cyclist, but not the other way around. Bez explains:
[Consider] the angle between the cyclist's line of travel and the line from their eyes to the vehicle which will hit them.
At this location, with this vehicle, it is 94 degrees.
A car which is on a collision course at Ipley Cross with a cyclist who is obscured from the driver's view by the front pillar will approach the cyclist from behind.
Ipley Cross is constructed in such a way that not only is it possible for a careless driver to drive straight into a cyclist without seeing them until a fraction of a second before impact, but under the exact same circumstances it is also possible for that cyclist not to see the car that hits them until the same moment.
If anyone were to take a highway engineer to a wide open space and ask them to design a junction which would readily enable two road users to collide with neither of them ever seeing each other, I doubt any would be able to manage it.
Yet this is precisely what exists.
This article has proven so popular, and drawn so much commentary (and trolling) that the author has gone back to address it all in an addendum. It's a lengthy read, but if you're interested in bicycle safety vis-à-vis infrastructure, I recommend giving it a read.
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Very weird, but I was knocked off at this Junction Feb 2014... in exactly this manner. Commuting to Yacht design studio in Beaulieu, guess I will post story on singletrack.
I get annoyed by A-Pillars on round abouts as I often find myself craning my neck, so I do understand the argument here, but as you can see on the arial picture, there is a STOP sign and STOP markings, not a give-way line, therefore regardless of visibility, the driver should stop!!!
Apologies for being pedantic ;)
Ever since the last episode of Grand Tour, when they noted thin A pillars on some supercar I've already forgotten being due to the all carbon fiber body/chassis, I've been wondering why we can't just have carbon fiber A pillars bolted into our steel body normal cars? Carbon fiber isn't THAT expensive anymore, is it?
Car manufact http://car-from-uk.com/ebay/carphotos/full/ebay83644.jpg http://car-from-uk.com/ebay/carphotos/full/ebay83644.jpg http://car-from-uk.com/ebay/carphotos/full/ebay83644.jpg urers (due to increasing regulator standards) continue to beef up the A-pillars to improve rollover safety. As a direct response to crash analysis of rollover incidents, this makes sense. People are still getting crushed by the roof when they roll? Increase the rigidity of the structure until they don't. How do you increase the rigidity? Thicker A-pillars.
Now, I'm sure there are a number of criteria dictating good visibility for the driver that prevent the A-pillars from getting too beefy, but I am strongly inclined to argue that in their current state, A-pillar design disproportionately factors the rare rollover incident over common-sense visibility accommodations for everyday driving.
When I drive my '08 Mazda3, which has pretty thin A-pillars by modern standards, I have a much harder time gathering data about my surroundings during daily maneuvers, be it taking a turn at a busy intersection or simply maneuvering around a parking lot.
In contrast, when I drive my '85 MR2, interior pictured here, I don't have to crane my neck or lean over the steering wheel. The vastly smaller blind spot triangle projected off of these tiny A-pillars makes me a much safer and more aware driver on a daily basis. Is it worth it for the sacrifice to my safety should I happen to roll this car? In my opinion, yes. But if you look at it from a car manufacturer's (or industry regulator's) standpoint - they're much less likely to be sued by the family of a cyclist struck and killed by a driver, than they are by the family of a driver killed in a rollover accident.
And that's the sad reality.
TL;DR - if you want to be more considerate to pedestrians and cyclists, drive a pre-90's car.
And before the inevitable "but modern cars have higher hood lines and no pop-up headlights so they're safer when you strike a pedestrian!" argument - I will always hold the position that having all the right tools to avoid an accident will always be a better safety feature than accident de-lethalising features. You can put an airbag under the hood of your high-hoodline fat-a-pillar 8000lb car and that will probably reduce the number of fractures a struck pedestrian suffers, but if you give me a low hoodline, tiny a-pillars, and excellent maneuverability on my 2500lb car, I won't hit the pedestrian in the first place.