Saturday, September 3, 2016

Flex Lanes or Contra-flow Lanes on Existing Bridges could Meet Transportation Need

Each time we have a crash or blockage on the Center or Marion Street Bridges, we go through a bunch of hand-wringing about "wouldn't it be nice to have a third bridge." Of course, relative to big-city congestion, even our crash-induced congestion rates short-lived and minor.

Detail from August crash (see below for more)
But each time we have these crashes and traffic gets backed up on one bridge, there are often aerial shots or other traffic camera shot that show easy free-flow traffic in the opposite direction.

These incidents illustrate ways we possess and misuse excess capacity on our existing bridges. The result feeds our false narrative that we need to build a super-duper expensive new bridge.

Again, we read in the June 2014 letter from the DLCD to the SRC team that
The second major step [in the UGB expansion process] requires that Salem prove that the need cannot reasonably be accommodated (language in both Goal 14 and in 660-024 implementing rules) inside the existing Salem-Keizer UGB. This is probably the most important and difficult step in the analysis. For example, the findings will have to show that the alternatives that involve widening the existing bridges only, or adding a new bridge next to the existing bridges in the urban growth boundary, do not reasonably accommodate the need.
The new Land Use Final Technical Report Addendum Section 4.4.2 on the proposed Urban Growth Boundary amendment does not discuss the fact that the existing bridges have tremendous contra-flow capacity that we currently make no attempt to use.

Because photos from crash incidents show this great unused contra-flow capacity, there is a kind of prima facie case that the existing bridges could reasonably accommodate our "transportation need." This seems like a very real omission in the Land Use memo and at the very least requires more analysis. To be silent on this is to fail to "prove that the need cannot be reasonably accommodated...inside the existing Salem-Keizer UGB." An attempt at this proof probably requires several analyses in addition to looking at Alternative 2A. As I remember it, the initial screening of Alternatives was not framed with this UGB requirement in mind. Not at the forefront anyway. This probably means that the early rounds of analysis did not give sufficient attention to the suite of operational actions and build alternatives inside the UGB.

(Simply to appeal to the fact that subsection in the DEIS discussed why a "two-way" alternative was dismissed doesn't deal with emergency or rush-hour contra-flow lanes. I'm not sure there was any serious investigation of what it would take to implement these. Even with our one-way grid, though, they must be cheaper than a new bridge. Heck, for a totally manual approach to contra-flow lanes, if you hired a team of 50 flaggers at $25/hour for a full day, four hours for morning rush and four hours for evening rush, that would cost $2.6 million a year. Even without any actual widening, for decades you could dramatically increase capacity for much less than the cost of a new bridge + debt service - currently estimated at $45 million a year.)

Crash from August, 2016

Note now little traffic is on the Marion St. Bridge (top)
that's wasted capacity!
(Devin Fadenrecht / Special to the Statesman Journal)
Crash from February, 2015

Traffic might be backed up some on Marion...

Some queuing and slowing on Marion Street
(Yet it's not even total gridlock)
But there's plenty of room on Center.

Free flow and wide space on Center Street
One or even two lanes could be used for west-bound traffic
(Both traffic cam clips from during the crash and lane blockage.)

Crash from May, 2014

Aerial from 2014 crash-induced traffic backup
Update, July 20th, 2017

Dang! It turns out in the main "Findings Report", there is a brief discussion of temporary two-way function. (Not finding this until now is a casualty of having to skim hundreds, even thousands, of pages of material in the document dump prior to the UGB hearing.)

In section Emergency Response:
Following two incidents in 2005 that closed the Marion Street Bridge, the city and ODOT jointly developed plans for converting each of the bridges to two-way operation in the event of a bridge closure. The plans, completed in 2007, are very complex and would take approximately three hours and dozens of staff to implement....

The difficulty in converting these bridges to two-way operation stems from their design as one-way bridges with several directional ramps feeding and off-loading traffic from the bridge spans. The one-way street pattern on the east side of the bridge adds to the complexity of a conversion to two-way operation.

Implementation of these plans would allow for continued two-way flow across the Willamette River, but with significant limitations. The capacity to move vehicles would be severely impacted, resulting in gridlock that could extend well beyond the area of the bridges. Safety would be compromised due to the complex nature of the conversion and resulting congestion. If a long-term closure is anticipated, additional modifications to the plans would be needed.
Why this hasn't been discussed more, and why it isn't being experimented with or modeled in order to find better solutions, is not clear.


Walker said...

More great analysis that is, nonetheless, far too generous to the bridge boosting brigade. A rational analysis, given our economic constraints and the vast unmet needs for dealing with our regional earthquake fragility, would simply take all but bridge build options off the table unless and until all non-build options had been seriously tried together and SHOWN, by real data, to be inadequate.

In other words, we would start with the premise that there could be no building of anything for cars until it had been shown that ALL of the following were inadequate to resolve congestion issues:

1) Electronic tolling on the existing bridges;
2) Staggered work shifts in the downtown state complex;
3) Incentives for a significant increase in telework usage
4) Incentives for ridesharing for cross-river commuters;
5) Commute trip reduction programs with real incentives in Marion and Polk Counties
6) A fully functioning transit system;
7) Strong and well-funded bike and walk to school programs
8) Strong economic rewards for teens who do NOT drive to school paid for by those who insist on doing so;
9) Active efforts to discourage parents from driving younger kids to schools
10) A robust network of protected bikeways such that young families with elementary age kids feel safe using bikes to travel throughout Salem.

Salem Breakfast on Bikes said...

You are right of course in a general way! (Though you omit right-priced parking, significantly.)

But the matter at hand is adjudicating the proposed UGB expansion.

So it has seemed desirable to try to identify every way that "meeting the transportation need" on the existing bridges has not been explored - and doing so in a mainly autoist mode. This means including some "low-build" and car-centric options for the existing bridges beyond Alternative 2A. Even if the expansion cannot be decisively rejected (though that would be a terrific outcome!), at least there would be ample reason for a remand and further study.

The problem is that Bridge Advocates will point to the current TDM/TSM assumptions of an 8% reduction. From their standpoint, these things in you list are already baked into the analysis.

Salem Breakfast on Bikes said...

Updated with the discussion from the main Findings Report of a plan for temporary two-way function.