1. People start sharing cars. Car numbers drop. Congestion reduces. We all get there more quickly.
Congestion reduces. Not necessarily.
To car share effectively the driver makes an extra urban journey to pick up the passenger (usually). That can exacerbate the school run problem locally.
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To car share effectively the driver makes an extra urban journey to pick up the passenger (usually). That can exacerbate the school run problem locally.
Good point, A. (may I call you that?)
Another example of why schemes that seem superficially attractive are not necessarily actually beneficial.
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To car share effectively the driver makes an extra urban journey to pick up the passenger (usually). That can exacerbate the school run problem locally.
Depends on the relative locations of the homes and the school, but in most cases the overall car mileage is reduced significantly. In nearly every case it will reduce congestion at the pinch-point outside the school
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the overall car mileage is reduced significantly
Yes, granted, but at the expense of more local traffic in general.
And on my journey to work, all the congested bits are on the local roads. The trunk roads & motorways are usually relatively clear.
And, of course, the local roads are the ones along which children are walking to school. I thought we wanted to keep cars away from them? ;-)
In nearly every case it will reduce congestion at the pinch-point outside the school
Only if schoolchildren car-share. But I thought the proposal was to impose "2 plus" lanes on trunk roads & motorways? How many school runs use these roads? Some, admittedly, but enough to have a noticeable benefit?
I'm sure the reasoning will be quite good enough for HMG, though.
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>> the overall car mileage is reduced significantly Yes, granted, but at the expense of more local traffic in general. And on my journey to work, all the congested bits are on the local roads. The trunk roads & motorways are usually relatively clear.
patently, you're being mischievious again! You've conflated the school run scenario with commuting :)
On the school run, the distance is usually nearly all local -- so miles saved are miles of local traffic. Even in the least favourable scenario I can come up with, there is simply reduced gain, rather than a loss (see below)
Most commuters are heading into to cities, the opposite of your escape to the countryside. On city-bound journeys, congestion gets worse as you get closer to the destination.
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Worst-case scenario for two-child liftshare: mother of child A, located x miles from school, gives lift to child of mother B, who is Y miles in opposite direction.
Her outward journey is Y to collect child B, Y back to her own house, so X+2Y; the return home is X, so total is 2X+2Y
If both mothers drive their own child, then mother A does 2X miles, while mother B does 2X+2Y. Total car miles is 4X+2Y
So the lift-share always saves 2X miles, plus saving pollution from a second cold-started car.
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No, you are being mischievous.
Your original post:
"Special fast-track motorway lanes for car sharers are to be trialled" (my emphasis)
You justify these by showing the benefits of car-sharing on the school run. I don't see many shoolchildren in cars on the motorway. It's not me who is busy conflating!
Errr...
Granted, my commute is unusual. The proposed lanes will apply to me, too, though, else they won't catch people returning home.
Most commuters are heading into to cities, the opposite of your escape
Oxford was a city, last time I checked!
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No, you are being mischievous. Your original post: "Special fast-track motorway lanes for car sharers are to be trialled" (my emphasis) You justify these by showing the benefits of car-sharing on the school run. I don't see many shoolchildren in cars on the motorway. It's not me who is busy conflating!
Sorry, I was responding to the introduction of the school run into the equation. I guess we both got sidetracked!
However, I think that similar calculations apply to any local congestion caused by commuters sharing cars (but I'd be happy to be proved wrong). The only situation I can see where it causes increased local traffic is where a sideways journey for the pickup exceeds the local journey saved by not using a second car.
Oxford was a city, last time I checked!
sorry, I must be getting confused here. I thought you'd said a few wks ago that your office was in a small village with no shops
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>> Oxford was a city, last time I checked! sorry, I must be getting confused here. I thought you'd said a few wks ago that your office was in a small village with no shops
Yes, but on t'other side of Oxford. Oxford's congestion affects me.
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However, I think that similar calculations apply to any local congestion caused by commuters sharing cars (but I'd be happy to be proved wrong). The only situation I can see where it causes increased local traffic is where a sideways journey for the pickup exceeds the local journey saved by not using a second car.
You're confusing the global and the local picture.
The point (I think) was that carsharing does indeed reduce the overall mileage, as your algebra so clearly showed. However, it may increase the amount of rat-running around the local area before the then laden cars embark on their long journey to distant parts. Hence there is an effect on the school run and a detriment to the formerly healthy children walking to school.
We can't (here) reach a final conclusion on the merits*, but the argument was to show that the overall effect of a scheme is not straightforward to predict, and that apparently "good" ideas are thus not always necessarily so.
*and therefore I will shut up now. Cue cheers amongst Broomers far and wide.
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Yes, granted, but at the expense of more local traffic in general.
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patently are you not forgetting the one journey less that the 2nd person will be making locally?
as for traffic congestion/reduction on these high-occupancy lane roads, maybe people who have the 2plus passengers in the car anyway will have an incentive to move over to the "fast" lane and thereby make more room for the single-occupant cars in the other lanes? ! ;-) !
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Does anyone hold out any hope that HMG will rely on it, or can we assume that they'll just announce another source of fines, wave their hands generally in the direction of a superficially obvious benefit, and question the credibility of anyone who criticises it?
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This is interesting, as I was having a conversation with someone from Toronto the other day about the London Congestion Charges. They know all about these in Toronto, their government are seriously looking into doing a similar thing, and are keeping a very close eye on the London situation.
Did you know that the London CC is an utterly resounding success? London's traffic problems have been solved. The city is now more pedestrian friendly, and even the drivers are happier because there is more parking, and it is easier to get around the city.
That's what the Toronto public are being told. What's the betting we'll get the same unbiased view of car-share lanes from our government?
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Well, if they agree that majority of the drivers on motorway travel alone then why not help majority instead of minority? Who's to say that chauffer driven Jaguar or two crewmen VANs should have faster way of passage to the city than single Joe Nobody in Mondeo. It's just like buslanes in suburbs. 10 mile long queue of cars so almost empty chain of numer 2 doubledeckers can have longer break by the supermarket. Healthy priority. Obviously those that have time to travel by bus at 2 p.m must have more important businesses to attend than those who came all the way in cars. Don't they?
And why is it that we just pick up these dumbest of ideas and throw money at them instead of simply building more roads and motorways? Or maybe there a data that says number of cars will self reduce in the next years that we don't know about?
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If Ken or somebody really wanted to sort out congestion in London they would start with the traffic lights.
Decide which are they main routes and phase the light so that traffic travelling at the speed limit will have a green light each time: secondary advantage, makes it pointless exceeding the speed limit so all those Metal Mickeys can be got rid of.
Make the pedestrian crossing phase of the lights activated by the pedestrian pressing a button: no pedestrians=no traffic delay but the pedestrians get a fair crack of the whip when necessary.
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Well, if they agree that majority of the drivers on motorway travel alone then why not help majority instead of minority?
If a few more of us share cars there will be fewer cars on the road, so this does help the majority of drivers. Its also good for the environment. However, I agree that nicking the hard shoulder is a daft idea.
This could be trialled on the M4, by opening up that stupid bus lane for cars with 2 or more occupants.
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>> Does anyone hold out any hope that HMG will rely >> on it, or can we assume that they'll just announce another >> source of fines, wave their hands generally in the direction of >> a superficially obvious benefit, and question the credibility of anyone who >> criticises it? >> This is interesting, as I was having a conversation with someone from Toronto the other day about the London Congestion Charges. They know all about these in Toronto, their government are seriously looking into doing a similar thing, and are keeping a very close eye on the London situation. Did you know that the London CC is an utterly resounding success? London's traffic problems have been solved. The city is now more pedestrian friendly, and even the drivers are happier because there is more parking, and it is easier to get around the city. That's what the Toronto public are being told. What's the betting we'll get the same unbiased view of car-share lanes from our government?
Now I would happily commute to the London you're talking about...
could you just tell me where it is please?
JaB
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I saw a note in one of the papers that there is a possibility to pay a fee to use the 2+ lane for a one-up driver. Now this starts to smell of stealth taxing again - seems in the USA these are called Lexus lanes.
Martin
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pay a fee to use the 2+ lane for a one-up driver
Now I understand....
And it's been "pre-announced"...
Estimated implementation date = general election + 1 week.
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Now I would happily commute to the London you're talking about... could you just tell me where it is please? JaB
If I remember correctly it's reached by flying towards the second star on the right, straight on til morning.
Or, conceivably, it can be found in the head of a Canadian government official.
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some posts above have asked how the scheme would be policed?
i guess it would work on the same principles that most laws work:
most law-abiding people will obey it, you do not need 100% to obey the rules. in some cases just 50% can produce enormous benefits.
some people will disobey it all the time, and may occasionally get caught but still get away with it, or maybe sometimes pay a penalty.
or, as with speeding, many will exceed the limit at some point in their journey bu hope not to get caught.
in the real world case of the cities where it has been tested, it seems that the scheme is self-policing because other drivers who are gaining/losing make their displeasure clear.
you just need to do a few calculations with various assumed proportion of single-occupant cars obeying the rules to work out at which point the scheme can be considered a success and whether it helps all traffic flow.
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