Tuesday, January 20, 2009

Pattullo Bridge

Well, I’m sure by now you are aware that a section of the Pattullo Bridge burned down on Sunday. If not, do a quick search on Google. Anyway, the short of it is that the bridge will be out of service for over four weeks. I have to say that this must have really sucked for people stuck in traffic this morning and this evening. It was so foggy this morning that I couldn't get a good look at the bridge from the SkyTrain bridge. I’m sure there will be traffic issues for the remainer of this week. What will be interesting to see is what happens once people adjust to the reduction of this bridge in our transportation network.

In late 2007, the Interstate 35W bridge over the Mississippi River in Minneapolis collapsed. The bridge opened again in late 2008. There was lots of data collected about the change in traffic patterns and traffic equilibrium before and after the bridge collapse. Studies form the University of Minnesota found that there was there was there was “not disastrous disrupt[ion of] the overall traffic of the Twin Cities network as initially predicted by the mass media. Travelers exhibited great flexibility in dealing with the changed traffic pattern, although some encountered more inconvenience than others.” The report found that most traffic either made changes to travel time (to the shoulders of peak travel times), or changed their routes. The report did not find that there was an increase in transit ridership, instead drivers used the excess capacity on other roads and traveled slightly off-peak. Also, since the open of the new bridge (which is light rail ready BTW) it now has 1/3 less trips now then the old bridge had.

Back in the day (and even still today), planners and people tended to look at travel demand as a liquid. If you plug-up the pipe, that travel would spill over and you would have a big miss. The current thinking on travel demand is that it’s more like a gas. It will expand or contract depending on the diameter of the pipe.

Again, the closure of the Pattullo Bridge will have an effective on travel in our region. It will also have a short-term negative economic impact. There is will be longer commutes, but I think that we will all be surprised at how people’s travel will adjust to the loss of the bridge. Unlike Minneapolis, we don't have excess peak road (or really even transit) capacity. It will be interesting to see if we experience the disappearing traffic phenomena. Some people may try transit for the first time (hopefully they don’t have a negative experience), some people might car pool, others will decide that their trip is not worth taking.

I think the whole bridge fire highlights the need for a replacement bridge that must combine road/bike/light rail/rail (the Fraser River rail bridge almost rusting apart.) I also think that the bridge fire will show how flexible traffic really is.


rbo said...

just as long as they don't go through with the currently under-consideration removal of the HOV lane on hwy 1.

..... can we say, opposite to helping this situation? I can see it now.. "hey i know, let's punish people who carpool by delaying them, and teaching others that carpooling is evil!"

bregalad said...

It will take a long time to design and build a replacement for the aging Pattullo. By the time it's finished there will be another decade of growth and change in Metro Vancouver including a twinned Port Mann bridge.

My hope is that the new bridge is both a road and rail bridge with two sets of rails so trains will not have to wait half an hour for oncoming trains to clear the bridge. Such a new bridge would pave the way for expanded Amtrak service and a return of the interurban system on both sides of the Fraser.

Corey said...

Two sets of rails?!?

If we are planning for the future, we would need four sets, at minimum.

ngwright said...

Corey, you have to consider the existing rail infrastructure in New Westminster and Surrey. 4 sets of track would require a massive reconstruction on both sides of the water to ensure effective switching. Plus there is still extra capacity on the skytrain bridge. My concern is the compatibility and maintenance issues for a mixed-use crossing. We should definitely get on with this replacement, but I think two sets will probably do the trick if we improve access to the new light rail stations we're going to need.