A radical approach to junction safety - opinions wanted.

by Neil753   March 20, 2014  

We're reading about a number of safety initiatives at junctions; many of them quite complex, expensive, and all of them different and potentially confusing. I have an idea that could be applied to any junction, whether that be traffic signal controlled or a roundabout, and regardless of the existing road layout.

Install average speed cameras set to trigger at 10 mph through the junction.
Use the revenue from fines to install cameras at the next most dangerous junction, and repeat.

It's a simple idea that's relatively cheap, self funding, and easily understood.

Your opinions are appreciated.

8 user comments

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I'd rather all road users were watching the road rather than their speedometers.

Boardman CX Team '14 | Cannondale CAAD8 '12 (written off, SMIDSY) | Scott Sportster '08

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posted by Gizmo_ [814 posts]
21st March 2014 - 13:51

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Hmm for starters....

1) Its not illegal to travel through a junction at the posted speed limit, so the speed limit would need to be reduced locally.
2) They are not cheap
3) Average speed over distance cameras wont work over such a short distance
4) Car speedo's are not accurate at 10mph
5) Junction throughput would be ruined, junction capacity would plummet and massive queues would be caused.

posted by andycoventry [118 posts]
21st March 2014 - 13:53

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I would prefer the cameras that are triggered when jumped. There's a junction my way the record is sitting at 6 and all doing 30mph. As for roundabouts. A total redesign to stop them being sling shots for motorists.

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posted by giff77 [1046 posts]
21st March 2014 - 14:14

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andycoventry wrote:
Hmm for starters....

1) Its not illegal to travel through a junction at the posted speed limit, so the speed limit would need to be reduced locally.
2) They are not cheap
3) Average speed over distance cameras wont work over such a short distance
4) Car speedo's are not accurate at 10mph
5) Junction throughput would be ruined, junction capacity would plummet and massive queues would be caused.

1) Good point. I hadn't thought of that. I assume it could be done though, just like a 20mph limit past a school.
2) Fair point, although I notice that the average cost of altering the few junctions recently announced by Boris Johnson is nine million. Does anyone know how much average speed camera systems cost?
3) Good point. Do you know what the minimum distance might be?
4) I was imagining that there would be some margin to allow for that, by setting the trigger point slightly higher than 10mph.
5) The key is safety, rather than "throughput". If we can get people confident enough to ride bikes then most of the queues would disappear anyway.

Cheers for the feedback.

"Hey..... Let's be visible out there."

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posted by Neil753 [451 posts]
21st March 2014 - 15:01

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1) How about a bit of simple house-keeping to de-clutter the junction and the approaches to it?
2) Look to smooth out traffic flow even if this means a slower urban speed. If you can remove the stop start aspect then you will alleviate queues and the associated stress. 20mph sounds good to me (10mph is too slow).

posted by levermonkey [358 posts]
21st March 2014 - 15:22

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What are you aiming to achieve by lowering the speed? Is it to increase safety, or to encourage cycling? If it's to increase safety then there are better ways, as speed is often not the cause of injuries to cyclists at junctions - it's more often "didn't look properly" and a left-hook from a bus of HGV is still likely to KSI even at low speeds.

If it's to encourage cycling by those that currently don't it won't work as it's proximity of vehicles, not speed that 'feels' dangerous.

Cheap and easy does not equal best.

posted by teaboy [149 posts]
21st March 2014 - 15:26

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levermonkey wrote:
1) How about a bit of simple house-keeping to de-clutter the junction and the approaches to it?
2) Look to smooth out traffic flow even if this means a slower urban speed. If you can remove the stop start aspect then you will alleviate queues and the associated stress. 20mph sounds good to me (10mph is too slow).

I may be cynical here but the decluttering IMO will not work. The junction at the bottom of my street recently extended the double yellows by 200 meters on the main approach. All this has served to do is create an environment for motorists to speed through the junction. My own personal observations are that vehicles now progress much faster than before, an increase in RLJers and an increase in high speed collisions. The council still do not believe me when I tell them that they have it mor dangerous.

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posted by giff77 [1046 posts]
21st March 2014 - 15:38

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@ Gizmo
I agree. There's too many drivers constantly watching their speedometers. However, I'd like to think that since 10mph is the speed of an average jogger it might be fairly easy to gauge speed without looking at a speedo, which probably wouldn't be very accurate at 10mph anyway. If you rewarded drivers with a prize, if they could travel 100 yards in a car without a speedo, keeping between 5 and 10 mph, I suspect most drivers would get the prize.

@giff77
Good point. Maybe there's a system out there that could do both things (RLJs and average speed). Does anyone know?

@levermonkey
De-cluttering sounds good. Far too many signs at junctions. Too many distractions for the average driver to assimilate.

@teaboy
The aim would be to reduce the speed differential between different road users, providing more time to react to impending collisions. The potential closing speed in a 30mph limit is 60mph, for instance. I suspect most incidents happen because there's not enough time to react. I agree, slowing things down won't eliminate left hooks directly, but if everyone's travelling more slowly then everyone has greater situational awareness, which may well reduce left hooks indirectly. I agree, cheap and easy doesn't equal best, but if it was self funding it would free up money to be spent on other improvements that may hitherto have been unaffordable. Cheers for the feedback.

"Hey..... Let's be visible out there."

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posted by Neil753 [451 posts]
21st March 2014 - 22:24

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