The Z-line vs. the SMIDSY

[Horse]

I don't know if anyone else has seen this?

https://pure.royalholloway.ac.uk/portal ... xport.html

Also from Royal Holloway, this is worth knowing:

https://journals.sagepub.com/doi/10.117 ... 7611400917

Reduced Sensitivity to Visual Looming Inflates the Risk Posed by Speeding Vehicles When Children Try to Cross the Road
John P. Wann, Damian R. Poulter, Catherine PurcellFirst Published March 9, 2011

Abstract
Almost all locomotor animals respond to visual looming or to discrete changes in optical size. The need to detect and process looming remains critically important for humans in everyday life. Road traffic statistics confirm that children up to 15 years old are overrepresented in pedestrian casualties. We demonstrate that, for a given pedestrian crossing time, vehicles traveling faster loom less than slower vehicles, which creates a dangerous illusion in which faster vehicles may be perceived as not approaching. Our results from perceptual tests of looming thresholds show strong developmental trends in sensitivity, such that children may not be able to detect vehicles approaching at speeds in excess of 20 mph. This creates a risk of injudicious road crossing in urban settings when traffic speeds are higher than 20 mph. The risk is exacerbated because vehicles moving faster than this speed are more likely to result in pedestrian fatalities.

[Scootabout]

Our results from perceptual tests of looming thresholds show strong developmental trends in sensitivity, such that children may not be able to detect vehicles approaching at speeds in excess of 20 mph.

Interesting, but it seems they quote different speeds in different parts of the paper. Eg "children across all age groups, however, were able to reliably detect that a car was moving toward them only if the car was traveling at a speed below approximately 25 mph", and

"The thresholds suggest that when children do not fixate directly on approaching vehicles, or are in motion themselves, they cannot reliably detect the approach of vehicles that are 5 s away and traveling at speeds of 30 mph or higher."

[wheelnut]

For what it’s worth, while the Z line approach can be useful, the ones that worry me the most are the cars that come to a T junction just as you’re at your most vulnerable and look behind you.

[The Spin Doctor]

For what it’s worth, while the Z line approach can be useful, the ones that worry me the most are the cars that come to a T junction just as you’re at your most vulnerable and look behind you.

When threads collide... etc.

That's a good moment for using the horn.

[Horse]

There's some research on just that, comparing novice drivers who look all over the place with experienced drivers who only look where they expect vehicles to be.

And not just closer being an issue, if you're travelling faster than they expect traffic to be, then they may not search far enough away.

[The Spin Doctor]

There's some research on just that, comparing novice drivers who look all over the place with experienced drivers who only look where they expect vehicles to be.

And not just closer being an issue, if you're travelling faster than they expect traffic to be, then they may not search far enough away.

And if I remember right, the novices turned out to be better at spotting hazards... they just didn't know what to do about it. The experienced drivers saw what they expected to see... and got caught out by hazards outside their expectations.

The vast majority of riders killed in collisions in London were over the limit in a report a couple of years back, some by considerable amounts... but that included 20 limits which suggests that it wasn't just the result of a harder impact from the higher speeds.

[Horse]

Our results from perceptual tests of looming thresholds show strong developmental trends in sensitivity, such that children may not be able to detect vehicles approaching at speeds in excess of 20 mph.

Interesting, but it seems they quote different speeds in different parts of the paper. Eg "children across all age groups, however, were able to reliably detect that a car was moving toward them only if the car was traveling at a speed below approximately 25 mph", and

"The thresholds suggest that when children do not fixate directly on approaching vehicles, or are in motion themselves, they cannot reliably detect the approach of vehicles that are 5 s away and traveling at speeds of 30 mph or higher."

This gives the age ranges and results:

there was no significant difference in detection threshold for isotropic expansion in foveal vision between 6- to 7-year-olds and 8- to 9-year-olds. Children ages 10 to 11 years had a significantly lower (better) threshold than those ages 6 to 7 years, but had a threshold similar to that of children ages 8 to 9 years. Adults had a significantly lower (better) detection threshold than each of the three groups of children.

For isotropic expansion in extrafoveal vision, there was no difference in detection threshold between children ages 6 to 7 years and children ages 8 to 9 years, but both of these age groups had significantly higher (poorer) thresholds than children ages 10 to 11 years. Once again, adults had a significantly better threshold than each of the three groups of children.

[Scootabout]

Yes, children are worse than adults at detecting looming, but it was the speeds I was picking up on. Why? Because I get suspicious whenever I see arguments for 20 mph limits. And they specifically try to make that point (adding in the impact issue), despite not having consistently made it in the paper, it seemed to me.

[Horse]

Yes, children are worse than adults at detecting looming, but it was the speeds I was picking up on. Why? Because I get suspicious whenever I see arguments for 20 mph limits. And they specifically try to make that point (adding in the impact issue), despite not having consistently made it in the paper, it seemed to me.

The bit you quoted mentions 25 & 30

Oddly enough, this links back to Z Line

Part of the reasoning for '4 seconds' was how long it takes for a driver to check whether it's clear, get the car moving, then cross and clear your path.

And part of that was based on my infamous 11 month CBT, when I taught the trainee how to cross the road.

Literally, we parked, stood on the pavement, I asked her to tell me when it was ok to cross. I waited, gave up waiting, walked. Then we talked about how to judge distances, etc.

[The Spin Doctor]

Errr...

Isn't this simply 'learning' going on? People tend to think we triangulate to judge distance and speed when in fact for anything more than a metre or two away we use a kind of judgement based on 'standard size for the object we've seen' -vs- rate of change of that size.

I'd suggest it's no different from learning to catch a ball. 6-7 year olds usually don't catch well, young teens often catch much better and adults tend to be very good at it if they do a lot of ball sports.

[Horse]

As my mate Dr LabRat pointed out, when I said about something being obvious, until there's been research there's no proof

A bit like teenagers being irresponsible (and invincible), it's only in the last few years that brain imaging has allowed exploration of frontal lobe development to confirm what we already knew.

As an aside: when Filly was still teaching Juniors, they started rvery day with the BBC news website on the interactive whiteboard and chose a story to discuss. One day it was, IIRC, Highway Code questions. One was about stopping distances. A kid said that he couldn't visualise them (possibly not in those words), so they got a long tape measure and went out on the playing field to mark them out.

[The Spin Doctor]

What I meant was not that the research isn't valid, but it's not a 'special' case - simply a demonstration of how we learn spatial orientation skills within our environment. The unfortunate fact is that the only thing capable of doing 70 mph when the human brain was developing 200,000 years ago was a cheetah.

[Horse]

What I meant when posting is that it really emphasises the need to be careful if there could be kids about,. Also that they shouldn't be expected to have the same actions and reactions as grownedups.

[slowsider]

What I meant when posting is that it really emphasises the need to be careful if there could be kids about,. Also that they shouldn't be expected to have the same actions and reactions as grownedups.

They should be taught tactics to cross the road when it is clear. :ugeek:

[Horse]

What I meant when posting is that it really emphasises the need to be careful if there could be kids about,. Also that they shouldn't be expected to have the same actions and reactions as grownedups.

They should be taught tactics to cross the road when it is clear. :ugeek:

Nah. Learn by [surviving the] experience. And letting the NHS fix 'em

[slowsider]

What I meant when posting is that it really emphasises the need to be careful if there could be kids about,. Also that they shouldn't be expected to have the same actions and reactions as grownedups.

They should be taught tactics to cross the road when it is clear. :ugeek:

Nah. Learn by [surviving the] experience. And letting the NHS fix 'em

That's my story. But at 13.

[Horse]

The 'time to arrival illusion' supported this:



I believe that was also based on earlier work by Crilly & McGuire:

More on this illusion:

20201202_083232.jpg (184.8 KiB) Viewed 1142 times