Imagine this: You enter a major arterial roadway -- I-95 or Route 80 and you program your destination -- an exit #, a rest area, etc. Your car joins the pipeline, syncs up with all the other cars on the road, accelerates to a (fast) cruising speed (100+ mph), and you sit back and enjoy the ride. No lane-changing, no "human" failures (like slowing down just because the sun changes direction) - and when it comes time to arrive at your waypoint, the system safely gets you out of the flow and into a "manual" lane. Then you take over from there.
Could be awesome...
Highly automated steel-wheeled vehicle on steel tracks with continuous electricity supply along the way... I wonder how we'll call that.
Maybe technological advances have made it more feasible. I guess we'll see.
I thought its a nice idea and tried it. Unfortunately, I tried this in Tel-Aviv, where drivers from other lanes immediately moved their cars into the space that opened between my car and the one ahead of me. It didn't take me long to figure out that I'm getting nowhere.
Two years later, when I moved to the bay area, I tried it on the 101 during rush hour traffic. To my shock, it worked. It was exceedingly rare to have any car move into that space. Or move lanes in general. For some reason (laziness? safety?), California drivers don't switch lanes as much as Israeli drivers do.
Moral: There's time and place for every algorithm.
Bay area drivers have this weird sense of "lane ownership". They don't change lanes... and they don't let anyone come in! It's not the sort of "Won't let you cut in front of me!" that you sometimes see in Israel, but a general thing. Even if you need to change lanes to exit and it's clear you're going to exit right away, I've had countless drivers speed up and block me from merging to the right.
This weird quirk does make it useful for applying traffic wave theory, so at least there's one good outcome.
What generally happens is that from the moment I start doing this, overall traffic speeds up just a bit and the lane ahead of me clears fairly quickly. It's win-win for everyone but the hotshot behind me.
The optimal flow is for everyone to use both lanes up until the last moment, and then to merge by alternation (one car from one lane goes, then one car from the other lane goes).
Unfortunately, this only works when a substantial majority of the drivers understand that this is how it should work. If you don't hit that threshold, then the people who use the disappearing lane are going to get glares.
Here's a link that describes the theory behind optimal merge patterns:
If one or a few drivers in the empty lane start pacing the cars in the full lane, cars will build up behind them. When they arrive at the end of their lane, the drivers in the full lane won't be so ready to block merges (since nobody was cheating by racing down to the end.) Perhaps this could trigger an outbreak of zipper-merging.
He has updated it since '98, and even bought a domain! But yeah, it does work.
Your '95 Civic may not be announcing its velocity, but when the car behind you and the car in front of you have both read your license plate and agree on your speed, you may as well be.
What does ACC do? It imposes proper safe driving headway distance, as well as providing near-instant reaction time for braking. No tailgating, no accumulation of 1-sec human reaction times.
But couldn't human drivers do the same by simply padding out their 2-sec spacing to 3-sec? And only a few need to do it.
The point where traffic stops then flows backwards along the freeway like a wave. You can see this if you have a long view of the freeway ahead.
So what I'd do is slow down in advance of the wave reaching me, and try to time it so that the traffic starts moving again before I reach the stoppage. Many times, I've been able to stop the wave from progressing by doing this.
If you commute along a stretch of highway every day, then you know exactly where the "stop waves" tend to appear. That's the place where you stop driving like a Wolf, and instead drive like a Shepherd: stop speeding and tailgating, and instead open up a large buffer.
I've found that this works well in some places. The other drivers seem to know what you're doing, and sometimes you'll even see others using the same technique. But in other spots everyone seems clueless, and they'll race to fill up the tiniest hole.
Also, as with the Koshima monkeys washing potatos or Blue Tits & milk bottles, in the last ten years the trick seems to be spreading. Some of our "clueless" regions have experienced a state change, and the daily jams seem to appear less often.
I wonder if the articles below have a simple cause:
In practice, they'll implement encryption and authentication, then make it a federal crime to mess with it.
As a child, I used to dream of such a device as I sat impatiently at traffic lights in the car (naturally asking my parents "are we there yet" every 5 seconds). I was pretty excited to learn that it is a real thing!
Things like this could possibly save Millons of hours a year. Quite powerful.
Just encourage people to use defensive behavior when they see a jam up ahead, and optimistic behavior as they leave the jam.
Sure, that's limited to people's line of sight (in the case of approaching the jam), but it's better than nothing.
Interestingly, I've been assuming both optimal behaviors intuitively. When I see a jam up ahead, I slow down well ahead of time, hoping that by slowing now, I'll avoid a full stop up ahead; similarly, as soon as I get out of the jam, I speed up quickly. Seems like the natural thing to do after a traffic delay.
In my experience, not a single person follows those signs. Everybody just keeps on going at full speed until they're forced to stop.
It would be a lot better (for everyone!) if cars were driven by machines that followed those rules properly.
How would one explain the why and how of Traffic Waves in such a small space? And don't forget to include a shout-out to trafficwaves.org.
"I drive nice 'n' slow to avoid the stop 'n' go."
"I drive slow 'n' steady when traffic's getting heavy."
There's a legal solution - create cameras that detect tailgaters, and fine them. That will encourage people to leave more space, which will give everyone more room to maneuver. Country-town car spacing = country town speeds, not the ~10mph you get in city centers.
More discussion at reddit: http://www.reddit.com/r/math/comments/k6ked/can_you_guess_wh...
No new computers needed, and fewer "optimists" rear ending people.
People drive at a constant speed.
The root cause of traffic jams, in my opinion, is that people brake much quicker than they accelerate.
This leads to traffic bunching up, and then stretching out as people regain speed.
In the UK, the variable speed limits on major routes work if people obey them, as it cuts down this emergent behaviour.
There is actually research about this, like http://papers.ssrn.com/sol3/papers.cfm?abstract_id=577201
If the traffic pattern is so saturated that people rush into the space you leave, leave space anyway. Leave more space.
People seem to want to optimize for "average distance from the destination". That doesn't get them there any quicker.
You certainly don't drive where I live.
Looks like he's redesigned his homepage since I got my degree, so I can't immediately find the animations he used to have to illustrate the method.
That's going to be the biggest problem. Automatic driving of cars isn't a technical problem where you need to tweak something, it's a legal problem.
A lot better way to dissolve would be to show the drivers the traffic jam on the map so they take another way that is free. This is the main idea of this system:
I have used it and it really works, because you can see the traffic jam in advance and plan another route (or the navi can do it for you).
Currently people use brake light to signal and detect slowdown ahead, but sometimes people slow down without hitting the brakes. Displaying flow speed every 500 or 1000 feet on the side of the road would give fore warning on traffic slowdown ahead.
Yep, just as soon as we have cars that can not only drive themselves, but we trust enough to cede control. Next generation? I doubt it.