The Preferred Alternative is an Expensive Damp Squib

So one of the things that stands out in the Traffic and Transportation Technical Report Addendum is the fact that the improvement the Preferred Alternative generates is not actually all that striking. It might be nothing, in fact.

Shouldn't there be more green???
In 2040 close-in the Bridge significantly helps 5 intersections
and makes 4 of them much worse during the morning rush.

Even when you accept the internal assumptions and traffic modeling of the SRC, the number of key intersections that operate with acceptable volume/capacity ratios isn't as big as you'd expect for a $500 million investment.

If there's any kind of scoring for cost/benefit or return on investment, the Preferred Alternative wouldn't actually score very well.

The Traffic Addendum shows four maps with a set of key intersections rated for "meeting mobility standards." (You'll notice the numbering of the maps is non-consecutive; I think they are ordered in a way that hinders apples-to-apples comparison.)

Figure 4.2-1: Projected 2040 AM Peak, No Build

Figure 4.2-4: Projected 2040 AM Peak, Preferred Alternative

For the morning rush, I look at the Preferred Alternative and see more intersections failing with red and yellow (still not meeting the mobility standard, but showing "improvement") than green!

Figure 4.2-2: Projected 2040 PM Peak, No Build

Figure 4.2-6: Projected 2040 AM Peak, Preferred Alternative

There is more "improvement" in the afternoon rush with the Preferred Alternative, but still not as much green as you'd expect for an investment of $500 million.

The Traffic Addendum summarizes this citywide with Vehicle Hours of Delay and Vehicle Hours Traveled (Section 4.4.2.1):

Of the three measures, VHD provides an indication of level of congestion system wide. Overall, the preferred alternative AM Peak VHD would experience a 12-percent reduction and a PM Peak 3-percent reduction compared to the No Build Alternative. VHT for the preferred alternative AM Peak would experience a 3-percent decrease and PM Peak would experience a 1-percent decrease compared to the No Build Alternative. VMT for the preferred alternative AM Peak and PM Peak would experience an increase of 1 percent.

Let's repeat that:

• The preferred alternative AM Peak VHD would experience a 12-percent reduction and a PM Peak 3-percent reduction compared to the No Build Alternative
• VHT for the preferred alternative AM Peak would experience a 3-percent decrease and PM Peak would experience a 1-percent decrease compared to the No Build Alternative.
• VMT for the preferred alternative AM Peak and PM Peak would experience an increase of 1 percent.

Basically, for $500 million, we are dealing with changes of 3% or less in all but one measure, and the exception is only 12%.

Traffic modeling doesn't come with 95% confidence intervals, but it would surprise me if these estimated differences are statistically significant. They are nearly certain to be within the margin of error for the modeling.

So, a hypothesis:

Given our current traffic modeling, we propose to spend $500 million on a project with no statistically significant benefit.

By itself, I think a delta within the margin-of-error shows there is no "need" or that the "solution" requiring an expansion of the UGB is no actual solution.

According to the June 2014 letter from DLCD:

Goal 14 includes two "Land Need Factors" which state:

"Establishment and change of urban growth boundaries shall be based on the following:
"(1) Demonstrated need to accommodate long range urban population, consistent with a 20-year population forecast coordinated with affected local governments; and
"(2) Demonstrated need for housing, employment opportunities, livability or uses such as public facilities, streets and roads, schools, parks or open space, or any combination of the need categories in this subsection."

A need must be established under both of these criteria before a UGB can be expanded.

How do you establish a need with a project that costs a lot of money but doesn't change anything?

Maybe the argument needs to be refined in some of the details, but the outline has to be obvious: A project that doesn't create meaningful reductions in VMT or VHD over doing nothing doesn't merit a UGB expansion.