h a l f b a k e r yYou could have thought of that.
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
This idea is designed for freeway/road systems that are far over capacity. One major cause of congestion is overloaded offramps. The problem is that cars can't exit fast enough, usually due to some constraint after the exit. This backs up into the freeway, and causes the entire freeway to slow down.
This
system starts with multiple lanes for all major on-ramps. Each lane is marked with a destination (downtown, Interstate-5, other, unknown, etc.), and has a stoplight. A computer controls how frequently cars are allowed to enter the freeway, so that there is no backup at exits.
The only issues I see with this is space (not an insurmountable issue) and enforcement. For enforcement RFID-type chips would be ideal, but license plate character recognition should work fine. You're allowed to change your mind twice per month, or you are ticketed (the "unknown" lane is exempt from this, but lets cars through slower).
Metered on-ramp
http://home.att.net...an/h_imgs/meter.jpg
Like this, but a bunch of them with destination signs. [Worldgineer, Nov 01 2006]
Desynchronizer
Desynchronizer
There should be a fast and slow lane, not just "two lanes" when driving abreast. [reensure, Nov 08 2006]
[link]
|
| |
Many motorway interchanges in UK have traffic signals on the off-ramp, and many have each lane being for a specific destination. |
|
| |
On the off-ramp? That would make things worse. |
|
| |
1) Your wait time doesn't change - the difference is that you're waiting on the on ramp instead of the off ramp. Because this system will clear the freeway you'll actually get home faster. |
|
| |
2) They know where you're going when you're sitting on the off ramp. Is this a serious concern? |
|
| |
3) Violation of your freedom? Certainly not more than toll roads. Wait in the unknown lane. Besides, driving isn't a right. |
|
| |
//On the off-ramp? That would make things worse.//
Most UK motorway off-ramps lead onto a roundabout; if the traffic on the roundabout is particularly heavy, traffic leaving the motorway would have trouble getting onto the roundabout, so the entire roundabout is light-controlled. |
|
| |
Exactly the problem I'm trying to solve. Here, often there is a stop light at the end of an off-ramp. This backs traffic up to the freeway and slows the freeway down. |
|
| |
I'd like a system that takes over control of the car as soon as you hit the motorway. Seat turns around, time to read/take a nap. |
|
| |
//Exactly the problem I'm trying to solve.//
Likewise. The point is not that there's a stop-light on the off-ramp but that there's a linked stop-light on the road that the off-ramp traffic is joining, without which it would be stuck on the off-ramp for longer. |
|
| |
Right, but if nobody was let on the freeway that was travelling to that offramp until the roundabout was less busy, that should help things. |
|
| |
I'm not being snarky, but do you have roundabouts in US? Specifically, do you have them as interchanges? |
|
| |
They're quite rare. I've seen only a small handful in the US at any significant intersection, and never next to freeways. One thing I like about Seattle is that in the older neighborhoods there are tiny ones instead of stop signs. |
|
| |
So I could certainly be missing the intricacies of the roundabout, having only seen them in action when driving in Italy. |
|
| |
yes, i have been stuck on onramps, but i
believe this would make traffic worse. |
|
| |
i have always wondered though: why
Hawaii has an interstate highway? |
|
| |
Of course you've been stuck on on-ramps. That's the whole point of metering lights on on-ramps. Are people really not understanding this idea? |
|
| |
I think that keeping cars off the freeway on grounds of their destination is discrimatory & it penalises drivers unnecessarily. |
|
| |
I live near the M8, in Glasgow, Scotland - and it has quite a few on ramps with traffic lights that only operate at peak times. This is especially prevalent as the motorway snakes through the city, with on and off ramps on *both* sides of the main road. It also has a dual lane off ramp that goes down to one lane, witha a merge-in-turn. So that aspect of your idea, as you point out, is baked (it's called ramp-metering). |
|
| |
But the crux of your idea, as I understand it, is the queuing system. I haven't worked through the logic yet - but I suspect that the effect on traffic you are looking for is an illusion. |
|
| |
Lets consider an on ramp N, with awating traffic T(exit): I hypothesise that the differentiated queuing won't make any difference to the traffic impact for at least the immediate junction (N+1) (all traffic entering the freeway has to be on for one junction). Then if we consider those leaving at the second junction (N+2). Since T1 have now left the freeway, the traffic between junction N+1 & N+2 increases by Tn-T1 + T(n+1). |
|
| |
What I think I am saying is that the traffic has to get on the freeway - it doesn't matter where it gets off. To help regulate flow, all that is needed is a single traffic light system to guarantee a maximum traffic arrival rate. |
|
| |
Unless you apply the system to the entire motorway - so that you know , in advance, what the congestion will be at the exit lanes. |
|
| |
But then that requires an estimate of journey time and assurance that the car will leave the exit that it was scheduled to exit on. |
|
| |
This would be a mammoth calculation and would be built on some rocky assumptions. |
|
| |
// requires an estimate of journey time and assurance that the car will leave the exit that it was scheduled to exit on// Now you've got it. This will need some complex calculations, but computers are great at that. Optimization routines are already used in on-ramp metering, this would just require more of the same. |
|
| |
//discrimatory// Not in the slightest! In fact, I consider the standard system to be an unfair and ineffective system. Consider a single route. Under my system, if I have to wait on an on-ramp, it's only because I'd normally have to be waiting on an off-ramp. The metering has just moved the location of my wait off the freeway. Now consider the person that travels to the exit after mine. Under the standard system, they'd have to wait for me while I wait on the freeway to get to the off-ramp. Under my system, they are no longer punished by my commute - their off-ramp is always clear (perhaps it isn't a heavily used route), and so their lane has no wait. |
|
| |
The result? I've waited just as long (or a shorter time, if there were normally other bottlenecks in the way), and the other person's commute is shorter. The freeway is constantly moving at full speed, rather than waiting at bumper-to-bumper speeds. You call this discrimination, whereas I say we've removed unfair persecution and used the roadway more effectively. |
|
| |
I'm pleased to say I've never been hung up on a freeway ramp -- such incidents are rare in my area and typically happen only when a crash snarls all right-lane traffic. The highway department also is served by innumerable 'public notice' signs near major interchanges than can be used for traffic warnings, advisories, or alerts. |
|
| |
[Worldgineer] If ... and sorry if you think _your_ idea is misunderstood ... people had a bit more consideration as to their purpose for being on the road, much of your gridlock would resolve spontaneously. What your Idea suggests is tantamount to forcing good drive planning onto drivers who've not taken the time to understand where they're going and to align themselves in the proper lane. My morning drive varies by 20 minutes solely depending on the degree (number of encounters) between me and a phalanx of vehicles led by drivers who've put themselves into the wrong lane for where they've thought to turn, and they continue to drive for miles trying to let everyone behind the 'squeeze' by one side so they can finally move to the other lane. The worst are those who sidle up and drive abreast of one another (see my link). |
|
| |
Education or good sense is necessary to defeat road rage, but I concede that roads planned to shuttle drivers quickly in unfamiliar settings offer some hope. |
|
| |