Monday, April 18, 2011

Back to basics on the bridge

Last week the rail span of the Johnson St. Bridge was closed for safety reasons.  The rail stopped using it a few weeks ago and service has been suspended, at least temporarily, while the Island Corridor Foundation that owns the rail line scrambles to find funding for track fixes well beyond the bridge.

While the bridge may have been safe for cyclists and pedestrians to use for awhile longer, perhaps a few weeks or a month, the prudent approach was to accept the advice of the engineers of record and close the bridge.  It's a cautious approach and ensures life safety issues are addressed, protecting our citizens (as well as reducing our exposure to liability issues should the bridge fail without warning).

We're ahead of the game here, not so much like Minneapolis where the I-35 bridge collapsed in 2007, killing 13 and injuring dozens more.  I've covered that one elsewhere in the blog or on my website.

What's got me back on the bridge is the rise again of what I believed to have been a dead issue.  More than one council colleague raised the prospect of closing one lane to provide some separation for cyclists and, I think for some, the idea that it could be shared with pedestrians.  More on some of the design challenges in some blogs in the days to come, but first I wanted to address one of the flippant comments made during our discussion of what to do.  So far, a lot has been done already, with signage and on-road improvements to remind everyone to slow down and share the road while we wait for the new bridge.  Most cyclists I've talked to are very enthusiastic about the rapid response and the effectiveness of the new treatments in making their commute a little more comfortable.

More than once though, I've heard, to my frustration (and expressed in most unparliamentary language), that "they can do it on the Burrard St. Bridge so we can do it here" for one, or  "we took a lane away on Fort St. and it works there so it can work on our bridge".  Neither comparison stands up, however and you can find some photo links here that illustrate some of the differences.  Traffic operations don't lend themselves to simplistic solutions and misplaced comparisons.

The volume, lane capacity and intersection dynamics, particularly on the downtown side of our Blue Bridge will break down if we close a lane, not to mention, yet, all the other design problems of viewing the bridge in isolation from the surrounding road and sidewalk network.

The Burrard St. Bridge, by way of comparison, has six lanes to our three, but more to the point, when the bike lane pilot was introduced, lane capacity was cut by a third (taking one of three outbound lanes is the important factor to understand), while proposals for the Blue Bridge would take away half the capacity available for outbound traffic - and in close proximity to nearby downtown intersections, and those feeding, steadily, five lanes of traffic into the bridge.  (The single inbound lane is the opposite - it feeds several lanes so has all the relief it needs from congestion pressures, not to mention a long approach where vehicles can store if traffic is busy or, what is another key to our crossing, when the bridge is up and all traffic is stopped).

Here's what Burrard used to look like - and you can count the lanes.  It's just not like our bridge and not a useful comparison.  The math doesn't add up.

Fort St., another project used for comparison also doesn't add up for our bridge.  It's still 3 lanes, allowing for some traffic to be drained off to left turns during peak hours, and carrying about a quarter to a third less traffic than is using the blue bridge.  Again, the math doesn't work.  Here's a quiet moment on Fort.

And here's where the traffic that uses the bridge fits into the road dynamics on the west side.  It's useful in understanding how and why traffic keeps moving over the bridge through Vic West and into Esquimalt in afternoon peak hours.  The math should be pretty clear.  It's not something that would fit on the bridge itself, let alone the nearby street grid on the downtown side.  Intersections are too close, and feeding too much traffic onto the bridge to make it work.

More to come in blogs yet to be written, but I'll continue to argue, so far successfully enough, that our engineers shouldn't waste their time looking at two lane trials to solve a temporary problem while we wait for a new bridge.  For some, it's about clinging to an idea that the best research has already proven unworkable, but still looks like a pot of (fool's) gold at the end of the rainbow.

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