Stephen Rees's blog

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

Traffic congestion at eight-year high

with 8 comments

Silicon Valley MercuryNews

Sorry about the size of that image but that is the “large” version. The red lines indicate congestion and the blobs have numbers indicating rank in the top ten.

Traffic congestion on Bay Area freeways in 2007 hit its highest level since peaking in 2000, transportation officials announced Wednesday, but tie-ups diminished on some of the area’s busiest corridors.

Now higher gas prices and a sliding economy mean that it is not as bad as last year now. But interestingly the response to all this congestion is not to build more freeways

The Bay Area will benefit from $1.3 billion in highway funding from the $20 billion statewide Proposition 1B transportation bond voters approved in 2008.

That funding will mean new car pool lanes on I-580 and major improvements in the way ramp metering, sensors and cameras are used to monitor and control traffic on I-80.

Basically the engineers have decided to go for the TDM tool kit. That’s “Transportation Demand Management” and it has been around for quite a while. It is based on the simple proposition that you should try to get the best out of what you have got before you start building more. So ideas like ramp metering are being applied – and are shown to work. Oddly enough we do have that on the Port Mann Bridge. But not before the Bridge where it would do some good, but after the bridge where it allows the traffic coming off the bridge to keep moving by restricting the rate of cars emerging from the Mary Hill ByPass. I think, and I could be wrong, that is more to do with basic road safety than traffic management.

And the story also has a link to a blog that is new to me that you might enjoy called “The Capricious Commuter”

Written by Stephen Rees

May 16, 2008 at 11:12 am

Posted in Transportation

8 Responses

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  1. Steven:

    The vast majority of the new HOV lanes are add-a-lane, not take-a-lane.

    Ray

    May 16, 2008 at 7:01 pm

  2. I started my summer job at the start of May. In Chilliwack. I live in Vancouver (Marpole) and I am commuting with another classmate who was also hired for the summer by the same organization.

    Technically we are commuting “against” rush hour traffic, but it certainly doesn’t seem like that, as most days I would say things are around level of service “D”. There has been at least one accident a day in each direction so far, and watching the thousands of cars pass by us every day going no faster than 40 km/h on a limited access freeway makes me shake my head at our folly in this region.

    Today was LOS “F” from Langley until after the Port Mann on the way home. As we drove into Burnaby over the Port Mann, I would say that probably one in eight or so cars (actually most were pickup trucks) in the HOV lane had only one driver. It’s a very frustrating thing to see.

    Driving through that traffic every day, the ongoing reaction in the back of my mind is “God, widen the highway already!” – and I am in planning school so that tells you what the average person must think about things. But of course I know this to be sorely mistaken, and the next thing I think is how great it would be if there were other options. Like the Interurban.

    But there aren’t. And by the look of things, there won’t be any time soon. My guess is that the “widen the highway” reaction is the most widespread one by far, and Gateway will go ahead as planned.

    By the way, my gas bill for this month (commuting only) is going to be around $400.

    Anyways, just wanted to give readers an idea what it’s like out there.

    I hope September comes soon.

    Corey

    May 16, 2008 at 7:03 pm

  3. A ramp meter on the 152nd st entrance to Hwy 1would go a long way to reducing the stop and go traffic. Ditto 104th Ave. I feel your pain Corey; with the traffic the way it is now (and gas prices too), I’m reluctant to take out-of-town visitors to destinations like Hell’s Gate or the Othello Tunnels anymore… Hell’s Gate… they should move that name to Port Mann.

    David Banks

    May 17, 2008 at 12:17 am

  4. I’d say ramp metering may increase overall demand since it increases overall freeway capacity (due to reduced merging slowdowns). But it can manage demand to some extent at the specific onramp it is implemented on, since it causes some people affected to change routes. Ramp metering would only limit overall demand if it was done on just about all congested onramps so overall capacity could be controlled.

    They can be quite beneficial for safety though.

    Bert

    May 17, 2008 at 8:54 am

  5. In general ramp metering ensures that queuing occurs on the approaches to the freeway as opposed to the freeway itself. Obviously it is a lot safer to have stationary traffic on a ramp rather than on a freeway lane, and it is preferable that freeway lanes move – if slowly – than become stop and start.

    I doubt that of itself ramp metering would actually induce more freeway traffic, though it might I suppose if the perception of moving traffic is less time stuck in congestion. In any event there is an upper limit to vehicle capacity which is approached at peak periods in peak direction on most water crossings in this region

    Stephen Rees

    May 17, 2008 at 9:54 am

  6. What we’re seeing from our modeling work in the Bay Area is that freeway ramp metering and other non-physical capacity expanding strategies seem to do a good job of reducing recurrent and non-recurrent delay, and thus improving vehicle speed and emissions. However, we are also showing increased VMT (VKMT) from induced travel.

    Click to access RTP%20Performance%20and%20Tradeoffs.pdf

    Ray

    May 17, 2008 at 11:17 am

  7. OK I was wrong. Induced traffic gets you every time. And the only way I know to combat that is road pricing

    Stephen Rees

    May 17, 2008 at 11:34 am

  8. It’s great to see that analysis is performed in advance of transportation projects in some places, rather than the “yeehaw, let’s do this one!” approach our Transportation Minister takes here.

    Bert

    May 18, 2008 at 10:47 am


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