Study suggests AI cruise control could kill traffic jams by cutting out the 'intuition' factor A multi-university research team has discovered the solution to traffic jams plaguing everyone's commutes: AI traffic managers that, rather than driving like impulsive humans, react to their surroundings to make traffic flow more smoothly. That's the initial suggestion from a five-day trial that took place in Nashville last …
You can't drive around compulsive lane bombers, let them drive past you and into the rear of the car in front of you. Is this AI (Adult Idiot) driving?
I think that Google sucks lots of ways but I open Google maps on my phone attached to the dashboard every time I drive and I never see any traffic problems that can't be easily driven around without even breaking the speed limits (LOL).
I once did a little experiment with lane switching. Whenever my lane was about to reach the pinnacle of its speed, I started to search for a gap to switch to the slower/stationary lane. The drivers in the slower lane didn't mind as they were not moving any way. Shortly after switch, the lane started to move and the other one slowed down. And I did indeed progress considerably quicker than the average.
But it's much less stressful to just stick to whichever lane I'm in.
For sure. The basic issue is that when you lane-switch into a gap, you automatically slow the traffic behind you in that lane, since you have to decelerate immediately to maintain a safe distance with the car in front, as does the driver behind you, as does the driver behind them, ... so you get a wave of deceleration propagating backwards in the queue. Whereas the lane you've left closes the gap but doesn't ultimately end up travelling much faster. Everybody loses (except you - maybe - but even then you don't win much).
Apart from lane-hopping, the worst offender is, as the article mentions, "intuitively" closing the gap to the car in front as much as possible. When you do that, then as soon as the car in front accelerates, you have a delay before you can accelerate (and you have to accelerate at a slower rate than them), since as your speed increases your safe distance to the car in front also increases. And the same for the car behind you, etc., etc., in a backwards-propagating delay-wave. Whereas, if you leave a larger gap, you can more closely match the acceleration of the car in front. I actually try to drive like this myself; it has the added advantage of being less stressful, albeit vulnerable to lane-hoppers sneaking in in front of you (◔_◔).
Anyway, all this has been known since forever. There's a large and mathematically-sophisticated literature on traffic flow and control going back more than half a century. My intuition (ahem) is that the "AI" scheme doesn't add much to this.
> I once did a little experiment with lane switching. Whenever my lane was about to reach the pinnacle of its speed, I started to search for a gap to switch to the slower/stationary lane.
Anecdotally, I used to spend a lot of time driving from Ipswich to Watford, which generally involved spending a lot of time sitting in a traffic jam.
The conclusion I came to was that the middle lane generally proved to be the fastest moving. And from what I could see, the reasons for this were:
a) the inner lane was full of HGVs, which are pretty sluggish when it comes to stop/starts - and there's also the fact that people in the inner lane often have to make room for new people joining the motorway
b) the outer lane was full of impatient people, who think it'll be faster, but who then cram together too tightly and therefore cause more stop-starts
Beyond all that, for me the biggest thing would be to somehow get people to obey the "2 second" distance rule; not only does it improve safety, but the additional space gives you more time to brake during a slowdown, which in turn increases the probability that you'll be able to smoothly ride out any sudden braking by the people in front, rather than having to jam on the brakes and trigger a cascade effect.
Alas, people tend to view said 2-second gap as a perfect place to stick their car, especially when it's busy and they're trying to get into the outer lane...
Yes, this is exactly what I have found in traffic queue too. In general, the middle lane is quicker for exactly the reasons you state and my own experience.
On the other hand, on a less congested 3-lane motorway, but not "clear" by any means, I'm finding more and more that lane one is nearly empty, just lorries, often well spread out, Lane 2 a bit more congested, primarily cars and vans, most of whom will rarely move back to lane 1 even when there's lot of room and time before needing to pull out and pass the next lorry. Then there's lane 3, where everyone who wants to drive to the speed limit or faster are nose to tail, often never quite reaching the speed limit because the traffic in 1 and 2 keep coming into lane 3 because lane 1 is doing 56mph "lorry speed" and the cars not in a hurry are staying in lane 2 doing 60mph with the occasional trip to lane 3 when a lorry is passing another lorry.
I would imagine the view from above is almost the exact opposite of what you'd expect in terms of numbers of vehicles in the lanes, ie 3 is busy, 2 is medium and 1 is nearly empty.
I try to drive far enough from the car in front that when they brake, I can just coast and use up some of my 'buffer'. Sometimes the driver behind will get impatient and zip round me as soon as there's a gap in lane 3 but they don't get very far ahead, but the again there are times when a whole line of us end up at a nice steady pace. Zero stress, and significantly boosts your MPG.
Here's one that will require a bit of additional AI training: the road has two lanes plus a left-turn lane. The left turn lane gets used as a third straight lane by people who do not want to bother with queuing in the other two lanes. But with the traffic lights not working because of load shedding, even the impromptu third lane is now congested. To overcome this problem, minibus taxis that want to earn money turn the pavement into a fourth lane.
FTA: "Last week's test added some new technology that made it into what Bayen described as a game changer: the vehicles coordinated actions between themselves, allowing them to react to conditions further ahead and coordinate their traffic influence network accordingly.
The AI-powered vehicles also incorporate information about local traffic conditions from the I-24 MOTION corridor where the test was performed, which is a section of highway equipped with 300 4K sensors for traffic monitoring."
In short, the autonomous vehicles are acting cooperatively and with greater information about traffic conditions, as opposed to humans, who generally act selfishly and with more limited information. Identifying similarities between this situation and other parts of the human condition is an exercise left to the reader.
Also FTA: "In that test six years ago, 20 cars on a closed circular track were driven by human drivers, and researchers noted the appearance of similar patterns to those on highways and busy roads. Adding a single AI-equipped vehicle to the test reduced congestion and led to a 40% reduction in fuel use."
i.e. even BEFORE this most recent modification, the AI operating on its own inamongst a bunch of human drivers was still able to improve traffic flow. And it's this improvement which is more mysterious than the one you'd bloody well hope you'd get as soon as you let multiple AIs communicate with one another and also feed them advance warnings about traffic conditions further along the road...
Drivers aren't paying attention. They brake late and too hard, followed by accelerating late and too fast. It progressively amplifies the slightest disturbance into hard stop and go ripples.
Also, a significant number of drivers don't look up from their cellphones quickly enough to avoid a collision. That blocks a lane for a while.
I'd hazard a guess that they were zooming up to the tail of the car ahead, then braking, causing the car behind to brake and the one behind and the one.......
It's amazing how many drivers think that getting closer==getting further ahead.
Or who fail the basic understanding that if you go 5 miles an hour faster it's going to take you an hour of driving to get an extra 5 miles closer to where you're going*, saving you all of about just 6 minutes if you can sustain it (but see above).
*Someone will probably correct my Maths, but the principle is the same.
The low-hanging fruit would be keeping a proper safety distance and never cutting off, which gives room to minimize braking. That in turn avoids creating a "red wave" behind you.
Given that the article also describes a system where the cars talk to each other, I would guess that they also increase safety distance when they know that traffic is slowing down up ahead. This would allow the slow wave from the slow traffic to dissipate faster.
They probably also avoid braking hard when they know that the driver ahead is not actually braking hard. Humans can't know that, so we always have to err on the side of braking harder than needed.
>> The low-hanging fruit would be keeping a proper safety distance
That! An anti-tailgating system that cannot be overridden
I see all the time where the "overtaking" lane is full of bumper to bumper cars that all have to desperately slam the brakes on when the line slows down, with the cars further back having less and less time to stop as the reaction time gets eroded each time.
Usually the left lane (UK here) is empty for quite a distance, so I usually pull over into it whilst they sort themselves out and the line of cars eventually sort themselves out.
I'm happy to wait a bit and get home on one piece
Ah yes. I routinely travel between jns 5 and 2 on the M1 s/b. A place where drivers seen unable to locate the left lane. It's mostly empty the whole distance, with the middle being full. And while I won't deliberately overtake on the left normally, in that lane, in that location I will sometimes go past them when they're crawling along nose to tail.
Much less stop/start (it's kind of harder to do in a truck so they don't unless forced to), less stress and pretty sure less fuel use. Every time you brake you convert expensive fuel into heat, so if you can avoid braking it saves fuel. In the end you won't lose much time if any, the truck drivers are as keen to get to where they're going as anyone.
Are the speed limits the same for trucks and cars in the USA?
On the right-side of the pond, the large vehicles have a speed limit roughly 10 MPH slower than cars - enforced by an on-board limiter.
So while it works, and you do use less fuel, there are two problems:
1) You get there noticeably later
2) You are regularly terrified, as a truck crawls past going 1 MPH faster than the truck you're following, boxing you in and leaving you absolutely no escape should it randomly decide to squish you.
The speed limit distance only matters if traffic is actually doing (close to) the speed limit. When there's lots of traffic and everything is crawling along, staying in the "lorry lane" is often a much smoother rid. Personally I don't like it as truckies tend to get distracted in traffic and my car makes for a feeble crumple zone between 2 trucks should the trucker behind me get distracted and decide to squish me into the space underneath the lorry in front.
Getting into a trucks slipstream really does improve mileage - it also tends to be slower. However, if you get TOO close then inability to see what is in front of the truck, human reaction time, and a trucks excellent brakes, you could be decapitated.
Mythbusters tried that one on
Only works if you are within 20 feet of the rear of the truck otherwise your are in the turbulence of its wake and any efficiency gained is lost
Sadly being 10 foot from a truck at 60 mph and the truck has to do an emergency stop...... you just have to do as the jokey sign says
"If you cant stop.. smile as you go under"
This is not true, if mythbusters say that then they are wrong,
Get on a motorcycle behind a truck, particularly an underpowered motorcycle and you can throttle back considerably and you don’t need to be as close as 20 feet from the Mansfield bars.
You can also feel the effect as less wind drag on your body.
And different trucks have different effects, the absolute best draft effect I found was car transporter trailers with few or no cars loaded.
> a trucks excellent brakes, you could be decapitated.
Not decapitated as trucks are designed to avoid that (at least in Europe), but people definitely underestimate heavy vehicles braking power.
Coaches avoid hate braking for passenger comfort and lorries because of load shifting concerns, but when I was in the emergency services aeons ago it wasn't unknown for intrepid drivers to end up eating fire engine when getting too close.
The most dangerous manoeuvre on a motorway is changing lanes. The less you can do the safer you - and those around you - are. I prioritise staying in lane over pinging in and out of the LH lane every 5 seconds where I can. That means noticing there are such things as "junctions" and moving appropriately.
"The most dangerous manoeuvre on a motorway is changing lanes."
Only if it's relatively busy and you are not paying attention.
That aphorism is about as useful as "Speed Kills". It sounds scary and, IMHO, is part of what has led to the endemic lane hogging we see so much more of these days.
Of course changing lanes is more dangerous than not changing lanes. But not enough to matter for a competent and aware driver.
Disclaimer: I've been driving 40-60,000 miles per year for the last 40 years and have never had a prang yet. I'm constantly expecting that to change, which may well be why it hasn't happened yet :-)
Yeah, that sentence missed out the all-important detail:
Humans are slow to react, so they overcompensate.
When the car in front slows down, you don't notice until you've got a few metres closer. So you have to slow down more than the car in front to maintain a safe separation.
So the car behind you slows down even more. If the traffic is fairly heavy, then eventually someone has to stop because nobody has left a large enough gap to absorb the delta.
When the car in front speeds up, the same happens but in reverse.
Adaptive cruise control already solves this pretty well.
"AI" brings nothing to the table, and in fact is simply dangerous. Knowledge of the average speed of several vehicles in front might help an adaptive cruise control algorithm pick a better target speed, but we're already into rapidly diminishing returns.
> Adaptive cruise control already solves this pretty well.
I use ACC all the time. I wish others did too. As things stand now, people keep overtaking me to get into my safety distance. Then, because they are not actually going any faster (my car was going at the current speed of traffic just like every other), the car has to slow down in order to regain safety distance. And the cycle resumes. Given that overtaking is relatively dangerous, this is... not optimal.
I have a very basic (& small engine car to try and keep emissions low) so no cruise control of any sort - but "manually" leave a safe distance ("2 chevrons apart" or less, depending on traffic speed) and in the UK get exactly the same issue on motorways, there's always drivers who, if they see a gap, can't resist jumping into it & screwing up my safe braking zone.
Until lots of people stop driving like bell ends, concertina effects will continue to be an issue.
There are a few efforts made on UK motorways to try and alleviate it with variable speed limits (though these can cause concertina effects themselves, e.g. when variable limit reduces often get braking based concertina mini jams created)
These cars are controlling traffic. The same can be done by reactive speed limits, in jurisdictions where drivers obey speed limits (so, not most of the USA). More overhead speed controls, slowing traffic approaching a wave trough, so that cars travel at average speed instead of high speed until the see the next traffic jam.
Surprised nobody's mentioned this. AI can look further ahead than humans and control the traffic movements more effectively. Basically the assumption is that humans are too stupid to drive and should be locked away while the robots deal with moving traffic around. Oh, wait a mo...
In SE UK if you leave a gap of 1.00001 vehicles length in front of you a van it invariably fills that gap. So, you leave a bigger gap behind the van because now you cannot see what the cars ahead of it are doing which was previously allowing you to drive smoothly,.... and 2 vans fill that gap. Pretty soon you have a typical M25 traffic jam. For many years I commuted by motorcycle which meant I could filter and traffic jams were just a slow section. Makes for a way less stressful commute until that truck turns right across your path and you end up in hospital. Personally I have found the perfect solution to the traffic jam. DON'T COMMUTE!
Humans are generally pretty crap drivers. Too easily distracted, lazy, temperamental, entitled, prone to over-react, and most are incapable of considering the consequences of their actions. Yes, I DO include myself in that but I do try to think ahead and consider the effects of my actions on those around me.
not as obligatory:-
CGP Grey... The Simple Solution to Traffic
Summary: if you can't get monkeys out of the driving seat, always try to maintain an equal distance in front and behind you.
In Washington, DC, the lights are timed, and if one gets onto the roads when traffic is light, one can travel a long way on a main road without stopping for a red light. However, light traffic seems to occur only after 10 pm and before 6:30 am (9 am on Sundays). When the roads are jammed to their usual rush hour capacity, the traffic is stop and go, and I doubt that any AI will make a difference.
I just want an AI that kicks in when an accident or breakdown occurs ON THE OTHER SIDE OF THE MOTORWAY, and provides a strong shock to the bellends in front who slow down to take a gander at it. In Chicago, the unnecessary complete stop on the other side of the road is a gapers' block, there may be other names in other places.
You dont need AI to keep traffic flowing you need a man with white gloves and a whistle. Seriously though, why is it that when the lights turn to green nobody moves? Many is the time I have pulled away at the green light only to find that the car in front is not moving. End result is only three cars through the lights and traffic bunching.
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