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Writer's pictureDavid

Bike volumes on Dunsmuir: the city <em>is</em> hiding something

The City of Vancouver has been kind enough to release bike volume data for the downtown separated bike lanes. Many people dispute these numbers. Here’s a perfect example:

First, the transportation department appears to be providing incorrect information about bike lane usage. We have our own 24-hour cameras that monitor Dunsmuir Street, and our results show that the city is wildly overstating the actual usage. Either our extremely expensive digital cameras are wrong, or someone at City Hall is fudging the facts.

I certainly hope no one would make this accusation without some factual basis, but I seriously doubt that anyone watched 24 hours of video, manually counting cyclists. According to the engineer in charge, staff regularly check the accuracy of their hose and wire counts and welcome anyone to come forward with evidence that the numbers don’t add up.

Canadianveggie’s detailed analysis points toward an upward trend in bike usage. My own analysis has been limited to eyeballing the numbers, but that was enough to see that the city is indeed hiding something. Look at the data on a block-by-block basis for September 22, 2010:

  1. 1,376

  2. 1,419

  3. 19

  4. 2,154

  5. 1,818

One of these things is not like the others. More specifically, Richards to Homer. There’s no way that’s accurate. Cyclists coming down Dunsmuir would never take a detour for just one block. I’m quite confident it wasn’t construction because I bike Dunsmuir every day and have never been diverted (well, not since the lane was officially opened). The same thing happened on October 7, shortly after Council approved Hornby. And again on the Granville to Seymour block from January 7-9.

So there you have it: the city is fudging the numbers. Down.

Ok, not exactly fudging. More likely it was vandalism or a defective counter. I’ve heard that some of the pneumatic hose counters have been found cut and had to be replaced by city staff. If anything, the inclusion of these low counts speaks to the accuracy of the data. That said, I think the city should annotate the published data with such incidents, as it does impact the numbers. Likewise for the handful of blank cells in the data — what does that mean? Perhaps the city doesn’t want to acknowledge instances of vandalism in case doing so motivates more.

In case you share my curiousity, Hamilton to Cambie is the busiest of the Dunsmuir bike lane segments with an average of ~1,400 trips per day. I’m guessing the extra traffic is from the Beatty bike lane. Richards to Homer and the Viaduct are roughly the same (~1,100/day), with Hornby to Howe and Granville to Seymour being the least traveled (~800 each). These averages include both weekdays and weekends.

Oh, and I tried looking for any influence from Critical Mass, but didn’t notice anything significant on the last Friday of each month. I suppose taking the bike lanes would be contrary to the whole “we are traffic” philosophy.

Besides the city annotating such data glitches, my other request would be for more granular data. It might reveal, for example, whether some cyclists are skewing the numbers (as some folk claim) by repeatedly biking over the same counter. I seriously doubt that’s the case, but even if it were, the overall numbers wouldn’t be impacted that much. The discrepancies I mentioned above result in a difference of over 4,000 trips, but in the grand scheme of things, that’s almost negligible.

Best of all would be live digital counters à la Copenhagen. (How about repurposing the Olympic countdown clock?) Sadly, even with such transparency, I’m sure bike lane critics would still dispute the numbers.

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