Why this British crossroads was so dangerous

Tom Scott
4 HN recommenders · recommended in 3 months, 2020–2025
YouTube
3.9M views · 6 years ago · explainer · evergreen

Tom Scott explains why a rural English crossroads kept producing cyclist collisions even though visibility looked fine. The angle of the junction and the car's A-pillar can hide an approaching cyclist, because there is no relative motion against the background.

HN people use it as the clearest visual of the blind-spot effect, and bring it up whenever junction or vehicle design and cyclist safety come up.

“This Tom Scott video shows how a cyclist can be perfectly occluded by the A-pillar while both are moving”
Urban design & public spacePsychology for designers
#roaddesign#blindspots#cyclistsafety#a-pillar#tomscott

15 comments from Hacker News

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@DoughnutHole2022 · in “Effects of large vehicles on pedestrian and pedal-cyclist injury severity”
Tom Scott has a good video for anyone looking for a visual of this phenomenon: ▶ this video He shows off a rural (and thankfully now fixed) crossroads in the UK with seemingly great visibility and an unusually high rate of cyclist fatalities - the roads are at such an angle that any reckless driving speed can align with a reasonable cycling speed such that the driver's door pillar can block visibility of a cyclist with right of way right up to the point of impact - and it's compounded by the fact that the car is necessarily approaching from behind the cyclist, so a passing cyclist will be unaware of the danger possibly until they get hit. Of course if drivers in the area actually followed the stop signs no one would get hit - but if you watch the video in a five minute period genuinely only about half of the cars passing through actually come to a complete stop at the stop sign. You need more than signage and quietly hoping that people to do the right thing.
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@zinekeller2022 · in “Tesla to recall vehicles that may disobey stop signs”
The Wired reporting is based on Bez's article on Singletrack (as stated): link Tom Scott made a good complementary video about this: ▶ this video It's already fixed just last month: link and link
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@sitharus2020 · in “Collision Course: a type of road junction that is dangerous for cyclists (2018)”
The Tom Scott video has a good animation on this: ▶ this video Because of the layout of the junction the cars are actually approaching from behind the cyclists.
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@open-source-ux2020 · in “Why this British crossroads is so dangerous [video]”
Submitted the video to Hacker News.
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@pfdietz2025 · in “Making an Intersection Unsafe for Pedestrians to Save Seconds for Drivers”
Example of an insideously unsafe intersection that was changed to make it safer (for bike riders): ▶ this video How it was fixed: link
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@notatoad2024 · in “California debuts 'turbo roundabout' to fix intersection near Bay Area”
this article seems to have some actual pictures: link the previous configuration as shown on the satellite image looks a lot like the intersection Tom Scott made a video about, where the intersecting road is angled to keep cross-traffic hidden behind a car's a-pillar. ▶ this video
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@bombcar2024 · in “Higher vehicle hoods significantly increase pedestrian deaths, study finds”
See ▶ this video for an example. One of the advantages of raking the front windshield for aerodynamics is changing the geometry for the A pillar to be more sideways instead of vertical, allowing a bit more hope of seeing something.
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@WirelessGigabit2023 · in “Vehicles with higher, more vertical front ends pose greater risk to pedestrians”
▶ this video Interesting intersection that had this problem (now fixed).
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@antiterra2022 · in “Blindspots on SUVs, vans, and pickups are bad for pedestrian health”
The blind spots in the article are from the A pillar, which isn’t addressed by rear view mirrors. The momentum would tend toward this being solved by sensors/computer vision, but maybe chip shortages have curtailed that. Tom Scott presented an interesting example of A pillar blind spots causing problems: ▶ this video
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k
@kibwen2021 · in “In 2019 40% of San Francisco traffic fatalities are from left turns”
> The angles we were converging at meant that he basically disappeared into the background because there was no relative motion. This effect is demonstrated in this video about a particularly dangerous crossing in the UK: ▶ this video
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@whymauri2021 · in “In 2019 40% of San Francisco traffic fatalities are from left turns”
For a particularly dramatic example of this, Tom Scott made a video about an intersection in the UK that's poorly designed for visibility: ▶ this video
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@matsemann2021 · in “In 2019 40% of San Francisco traffic fatalities are from left turns”
Sounds to me like cars shouldn't be allowed to drive where pedestrians travel, if they can't really avoid driving people over. Edit: This Tom Scott video shows how a cyclist can be perfectly occluded by the A-pillar while both are moving ▶ this video
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