Stephen Rees's blog

Thoughts about the relationships between transport and the urban area it serves

Archive for March 5th, 2009

Why no ramp metering before the Port Mann bridge?

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One of the oft repeated canards of the Gateway proponents is that congestion on the Port Mann bridge is bad and lasts all day. Neither statement has much truth to it. If you look at the detail it turns out that the bridge itself flows quite well most of the time – the congestion is worst on the bridge approaches. The biggest issue is the on ramp at 152nd Street. This is the last intersection before the bridge northbound – and traffic on the freeway is usually close to capacity at this point. In order to create congestion you only need to add a little traffic to a flow that is close of capacity.  Generally it is desirable that the flow on the main artery keeps moving and the queuing is confined to the ramp.

Many places use a traffic signal on the ramp to limit the nuber of cars that can merge into the freeway traffic at any one time. In Oakland, California a program to improve performance by the use of ramp metering is already demonstrating the effectiveness of this technique. Oddly enough the next intersection after the bridge (at the Mary Hill ByPass on ramp) has had ramp metering for some years. So it is clear that the BC MoT is well aware of how this technology works.

Before and after ramp metering

Before and after ramp metering

So if Port Mann congestion is a problem, why would they not have put a meter on the 152 on rampm as well? Probably for the same reason the a bus lane has not been built to get busses past the line up and onto the bridge. Again the myth perpetuated by Kevin Falcon is that bus service cannot be provided on the bridge because it would be too unreliable. But Translink has a scheme to put in a bus lane – and were ready to get on with when he stopped them.

The people who promote freeways have a very simple view of the world. Unfortunately it did not actually reflect reality – but they always stuck to their argument that more and better freeways would solve the problems that the current freeways have created. The logical fallacy is obvious to all but those who profit from construction of roads and low density sprawl.

The reason there is no meter on the  152 ramp – and no bus lane on the northbound hard shoulder – it that together they would have worked to reduce the traffic enough to weaken the case for a new bridge. After all to sure congestion all you need to do is get a few people to switch to transit – not convert everybody from car driving  as so many freeway advocates seem to think we are suggesting. Indeed the big objective for Translink when it was created was to get an overall share of all trips up from 11% to 17%. Actually not really that much of a challenge and one we could have beaten by now if Translink had been given the right resources and a decent plan. But the plans and policies seem to have been chosen in the most bone headed fashion to ensure that mode share has stayed almost the same over the last ten years and road spending significantly increased from the funds said to have been set aside for improving the transportation system for all.

Indeed in almost every part of the world where traffic congestion is a problem it has been conclusively demonstrated that expanding the road system does not work for very long – but a combination traffic managemnt techiques and additonal transit provision is both cheaper and more effective.

The Gateway is not about traffic congestion. It is also not about port expansion – which is increasing irrelevant. It is about continuing to facilitate low density suburban sprawl, which is what local developers understand and think they can get financing for. Many of these developers fund the BC Liberal party – and the right wing think tanks that like to throw doubt where no real argument actually exists. In BC black top politics has laways been the first resort of governments from both sidesof the spectrum and always prior to elections. It is monumentally stupid and self serving – and far too many fall for this open bribery with their own money.

Communities have been told that “something must be done” – and the one solution is always more roads. No one really admits that the other options have not be even examined properly  let alone tried. Most of the studies of traffic in BC are done backwards – there is a preferred “solution” and the only figures shown are those that support that. Even if that means suppressing or distorting information. For example, the Sea to Sky Highway was expanded – but the option to use rail was scuppered by ludicrous requirements. One alignment in a tunnel – which would have been cheaper and safer than what was built – was ignored in favour of a route which facilitated property development.  No one has ever seriously  examined rail for the valley – the studies almost universally were slanted to favour more roads. Although one exception recently was the City of Abbotsford’s Select Committee on Inter Regional Transportation (of which I was a member) which recommend surface rail for South Fraser Way – somewhat to my surprise.

Rail has a number of significant advantages. One is the much greater people carrying capacity of a right of way  (one 12 foot wide strip can carry ~2,000 people per hour as a freeway lane or over 30,000 people per hour as a train track). But also it can be electrified now using well known technologies for zero emission transport – something that is still science fiction for freeways. Yet we know that we will increasingly find oil scarce and expensive whereas ways of producing zero emission electricity are abundant.

It is one thing to favour your friends and supporters. We know all politicians tend to that direction – though most draw the line at outright corruption. But it is quite another when a set of policies is stuck to rigidly when it is clear that it does not deliver eiterh what iot promises or what is needed. And that is what is plain about the Gateway – and freeway expansion.

Written by Stephen Rees

March 5, 2009 at 11:15 am

Posted in Gateway, Traffic