Saw a broken down car way later than I'd have liked :o

[Mr. Dazzle]

Shouldn't be too difficult to project to the screen though it would have to account for the driver's height / eye line. (not eye liner!)

I was initially thinking about a HUD. My car has a HUD, but it only tells you speed, sat nav and stuff like that. It'd be pretty much impossible for it to draw a realistic stopping distance line because it has to know how tall you are. You can move the HUD image up/down and left/right just be moving your head.

Headlights on the other hand, are a fixed location on the car.

The lights on my car do actually 'zoom' in and out though. As you get faster on unlit roads the edge of the pattern get dimmer and it projects further ahead. The parking cameras also display lines which show the edges of the car. There's a red line on the screen, when you put that red line on an object that means the very back/front/side of your car is directly over said object.

So yeah - these are all elements of the same thing.

[The Spin Doctor]

Shouldn't be too difficult to project to the screen though it would have to account for the driver's height / eye line. (not eye liner!)

I was initially thinking about a HUD. My car has a HUD, but it only tells you speed, sat nav and stuff like that. It'd be pretty much impossible for it to draw a realistic stopping distance line because it has to know how tall you are. You can move the HUD image up/down and left/right just be moving your head.

Headlights on the other hand, are a fixed location on the car.

The lights on my car do actually 'zoom' in and out though. As you get faster on unlit roads the edge of the pattern get dimmer and it projects further ahead. The parking cameras also display lines which show the edges of the car. There's a red line on the screen, when you put that red line on an object that means the very back/front/side of your car is directly over said object.

So yeah - these are all elements of the same thing.

If you can have a camera 'spotting' oncoming cars as on the new Porsche system then it shouldn't be too difficult to fit an interior camera to calculate eye line. I think some cars already have cameras monitoring driver blink rate to detect sleepiness.

The 'stopping line' doesn't have to be perfect, just representative... most people follow far too close (like my other half - years of nagging and she still can't figure it out and drives up the arse of another vehicle until I say "you a bit close" and then she reacts, almost as if she hadn't noticed).

And I was watching a vid of a rider following a driver who was swerving all over the road at 60-odd mph just 30 metres back... on a wet road! A moment later the van ahead of him nearly had a head-on... that would have blocked the road instantly!

[Mr. Dazzle]

On reflection actually, my car already knows/considers your stopping distance.

If you start getting too close to the car in front it displays a little icon of "foot on the pedal" and "car" next to each other on the HUD. If you still start getting too close it makes the accelerator pedal less sensitive (i.e. you have to press it more to maintain speed), then it progresses to showing you a red triangle until finally it begins beeping as well to let you know it really means it

If you get really really close it'll let off the gas and/or brake regardless of what I do.

Before anyone says it, I'm sure you can turn all these thigns off. But I don't, cause, well, the car is correct!

[Horse]

If you get really really close it'll let off the gas and/or brake regardless of what I do.

Filly found out that her car does something similar.

Reversing in a car park, the car stopped with a dramatic bang! She had reversed almost into a frond of ivy sticking out of the bushes.

[iansoady]

I thought that was exactly what the thinking distance was meant to refer to? If not, what is it? Of course it may be over-generous.

[Horse]

I think some cars already have cameras monitoring driver blink rate to detect sleepiness.

If they don't already, there will be soon. Part of introducing automated systems to try and ensure the driver will be able to retake control (can't recall for sure, but 12 seconds rings a bell).

As well as blink rate, there's potential to log gaze direction e.g. distracted either inside or outside of the vehicle, and duration.

Some systems have the capability to detect / identify facial expressions. One quirk I read about was a look of almost amused disbelief ahead of shock / horror / panic.

[Horse]

I thought that was exactly what the thinking distance was meant to refer to? If not, what is it? Of course it may be over-generous.

Do you want to edit this to clarify which post you're referring to?

If mine about a bus, then yes. But knowing a number isn't the same as knowing and visualising a real-world distance.

[Mr. Dazzle]

I think some cars already have cameras monitoring driver blink rate to detect sleepiness.

If they don't already, there will be soon.

Yeah my car does. It films 360° around the car all the time, and you. If it detects a crash it records the previous X seconds of footage, time/speed/GPS location stamped, plus you. It'll totally nark on you

Also knows whether or not you're holding the steering wheel via capacitive sensors.

[The Spin Doctor]

I thought that was exactly what the thinking distance was meant to refer to? If not, what is it? Of course it may be over-generous.

The fact is that the 'thinking distance' in the Highway Code has always been mis-defined. It represents the 'muscle twitch' time, from the point that the brain sends out a signal to the moment the muscle it's talking to actually responds and begins to move a control.

If you want an example, it's the 'primed and ready' reaction time from the moment your driving examiner slaps their clipboard on your dash to signal it's time for the e-stop to the moment your foot begins to hit the brake. That's typically about 0.6 of a second.

When an emergency develops that we weren't expecting, there's an extra level of interaction - the cognitive delay in recognising there IS an emergency. That's before the reaction time and is up to 3 seconds. You might call this the 'uncertainty phase' - you don't know what it is that you don't yet now but there awareness that it might not be good.

See 'No Surprise? No Accident!' for more on this.

[iansoady]

I thought that was exactly what the thinking distance was meant to refer to? If not, what is it? Of course it may be over-generous.

Do you want to edit this to clarify which post you're referring to?

For some reason I can't edit the post. But I was responsing to Spin's point:

"As I keep reminding folk, it's actually worse than that because the Highway Code stopping distances refer to a PRIMED driver - that is, one who is EXPECTING to encounter a hazard that would force them to stop. "

In other words,taking the thinking distance to do this priming.

A bit under the weather so brain not quite in gear. In fact have just seen Spin's reply.

[Trinity765]

@Noggin Glad you and everyone is ok. I've seen and heard of many instances where the same scenario ended up with people not being ok. I hate traveling on motorways - car or bike. Most people zone out and follow the car in front thinking that they're safe. Not to mention how many tired drivers there are.

[Noggin]

@Noggin Glad you and everyone is ok. I've seen and heard of many instances where the same scenario ended up with people not being ok. I hate traveling on motorways - car or bike. Most people zone out and follow the car in front thinking that they're safe. Not to mention how many tired drivers there are.

I think the reason I was so worried about the whole thing was that, this is my job! I drive for a living, including motorways and in all weathers. It wasn't a perfectly timed transfer, but I wasn't particularly tired.

So now I'm just a bit worried about the next late afternoon transfer if I have to use the motorway!!

[The Spin Doctor]

@Noggin Glad you and everyone is ok. I've seen and heard of many instances where the same scenario ended up with people not being ok. I hate traveling on motorways - car or bike. Most people zone out and follow the car in front thinking that they're safe. Not to mention how many tired drivers there are.

I think the reason I was so worried about the whole thing was that, this is my job! I drive for a living, including motorways and in all weathers. It wasn't a perfectly timed transfer, but I wasn't particularly tired.

So now I'm just a bit worried about the next late afternoon transfer if I have to use the motorway!!

You need a Survival Skills 'Confidence Builder' course

Seriously though, has it happened before?

No?

So whilst a one-off isn't something to be complacent about, it's a pretty good sign you're not missing TOO much

Just try to re-program your brain to look for things that might be going wrong rather than look for confirmation they're going right... it's a 180 degree mindset reversal and really helps spot the anomalies.

[Trinity765]

@Noggin Glad you and everyone is ok. I've seen and heard of many instances where the same scenario ended up with people not being ok. I hate traveling on motorways - car or bike. Most people zone out and follow the car in front thinking that they're safe. Not to mention how many tired drivers there are.

I think the reason I was so worried about the whole thing was that, this is my job! I drive for a living, including motorways and in all weathers. It wasn't a perfectly timed transfer, but I wasn't particularly tired.

So now I'm just a bit worried about the next late afternoon transfer if I have to use the motorway!!

Don't worry - have a check list.

Tired? Have a kip and a coffee and if too tired (and I know this is easy to say) don't drive
Concentrate - switch the rest of life off before getting behind the wheel and don't rush even if late
Maintain a good stopping distance (inc. thinking time). AKA drive at a speed that will allow you to stop well within the distance that you can see to be clear on your side of the road
Keep your vehicle in good order - lights working, windscreen clean - fluid topped up, brakes
Have regular optician appointments
Relax and look up.

[Noggin]

@Noggin Glad you and everyone is ok. I've seen and heard of many instances where the same scenario ended up with people not being ok. I hate traveling on motorways - car or bike. Most people zone out and follow the car in front thinking that they're safe. Not to mention how many tired drivers there are.

I think the reason I was so worried about the whole thing was that, this is my job! I drive for a living, including motorways and in all weathers. It wasn't a perfectly timed transfer, but I wasn't particularly tired.

So now I'm just a bit worried about the next late afternoon transfer if I have to use the motorway!!

You need a Survival Skills 'Confidence Builder' course

Seriously though, has it happened before?

No?

So whilst a one-off isn't something to be complacent about, it's a pretty good sign you're not missing TOO much

Just try to re-program your brain to look for things that might be going wrong rather than look for confirmation they're going right... it's a 180 degree mindset reversal and really helps spot the anomalies.

Don't worry - have a check list.

Tired? Have a kip and a coffee and if too tired (and I know this is easy to say) don't drive
Concentrate - switch the rest of life off before getting behind the wheel and don't rush even if late
Maintain a good stopping distance (inc. thinking time). AKA drive at a speed that will allow you to stop well within the distance that you can see to be clear on your side of the road
Keep your vehicle in good order - lights working, windscreen clean - fluid topped up, brakes
Have regular optician appointments
Relax and look up.

I'm lucky with the company I work for as the vehicles are always good (and he's realised this year that ALL the vehicles need chains!! LOL)

It's definitely the first time, equally I've barely driven since the end of April, so probably do need to recalibrate a bit and a late afternoon transfer from Lyon (well, late afternoon drive there, early evening drive back) probably wasn't the best first trip to do!

I generally drive for the comfort of the passenger, and as someone that esily gets scared/carsick as a passenger, I never tailgate or drive too fast, so I'm ok with that.

I do think that the biggest issue was that it's such a long time since I've driven customers any distance.

Next ones will almost certainly be earlier in the day and on roads I prefer - I'm not a fan of long motorway journeys!


But thank you - things to think about

[Horse]

.
It films

Bet it doesn't

[Horse]

It's cause it looks like it's not getting closer until suddenly it's getting closer very quickly!

I was seriously horrified at how late I saw it.

There's a vision thing called 'looming'. It's one of the ways we determine how we are getting closer. Simply, smaller = further away.

But, as you'd expect, it's more complicated than that

When (if!) you see someone relatively small, like a car, it is just a 'dot in the distance' and is unlikely to be moving relative to the background. That's motion (or lack of) camouflage.

As you get closer, it will still be a 'dot' because it is only covering a small part of your retina. But when much closer, it will expand on the retina and 'pop out' - that "oh deary me" moment.

Well, this took a bit of finding. For an object 6 ft wide. See the pop-out Dazzle mentioned?

image size view distance.JPG (34.1 KiB) Viewed 608 times

Florida Highway Patrol
Emergency Lighting Research & Prototype Evaluation
March 2004
Lieutenant James D. Wells, Jr.

The imminence of collision with an object is specified in the optical flow field by an explosive rate of magnification called looming17. If a driver approaches a stopped vehicle ahead at a constant speed, this is accompanied by an accelerated rate of magnification. This explosive rate of magnification called looming has been studied to determine how it might provide time-to-contact information. Optical time-to-contact is called tau and tau at any given point in time of approach is equal to the instantaneous visual angle of an object to the driver's vantage point (in units of radians or degrees of visual angle), divided by angular rate (given in units of radians per second or degrees per second). This ratio yields seconds of time-to-contact. In physical (rather than optical) terms, this equates to range (in meters or feet) divided by range rate (in meters/second or feet/second), the ratio of which also yields seconds to contact. This is currently an area of research and evidence exists that people may use tau, optical expansion rate alone, or some combination of visual angle and expansion rate other than tau18. What is clear is that a) looming is a critical cue to collision, b) to avoid hard contact, looming must be cancelled through braking action or else the driver must steer away from the object.

The rate of change in image size depends on both speed of approach and viewing distance20. Consider Figure 1, which shows how the visual angle an object subtends at the driver's vantage point changes with viewing distance. This figure assumes a 6-ft wide vehicle viewed from an initial separation distance of about 1000 ft. The first point to note is that the relationship between object size and distance is highly non-linear. The second point to note is that the image size of the object does not change much for most of the approach, even though it doubles with every halving of the viewing distance. At 1000 ft, the object subtends about 0.006 radians or one-third of one degree of visual angle. At 500 ft, the image size doubles to about 0.012 radians or two-thirds of one degree of visual angle. At 250 ft it doubles again. Because of this nonlinear relationship, drivers may not realize they are closing in at high speed until quite close to collision.

[Mr. Dazzle]

S'just a bit of trig innit? The viewing angle is given by a tangent function, which has ^^^ that general shape (or perhaps the inverse of, depends how you quote it).

https://mathworld.wolfram.com/InverseTangent.html

[The Spin Doctor]

Don't forget the foveal pit is less than 5 degrees across... that's where all the clear and focused colour vision comes from. Anything that creates an image greater than 5 degrees is partly in peripheral vision!

Although by the time a car got that close to your eyeball you'd be hoping Chief O'Brien would be on hand to teleport you clear!

[Noggin]

S'just a bit of trig innit? The viewing angle is given by a tangent function, which has ^^^ that general shape (or perhaps the inverse of, depends how you quote it).

https://mathworld.wolfram.com/InverseTangent.html

Yeah, I never was any good at that kinda maffs!!