News Findings Support the Case for Boulevards in Seattle
Cary Moon and Julia Parrett over at the People's Waterfront Coalition have just sent out their weekly update, and it is exciting indeed. WSDOT has just completed traffic modeling on the scenarios listed on their website, and this news is good news! We've attached the full letter here, but here's a run-down on their conclusions:
- Of the whole shebang, there is only a +/-1% difference between any of the scenarios in terms of number of trips serviced. This is especially relevant because Gov. Gregoire has highlighted transportation efficiency as her number one objective. It is now impossible to use this reasoning to disqualify boulevard alternatives!
- The concerns about a perpetually snarled I-5 have been allayed. Two of the three boulevard options show no increase to I-5, and the third option shows only a minor increase.
- As for freight trips, the study concluded that only a very small fraction of the freight trips currently use the Alaskan Way, and that any alternative could service them as adequately as is currently the case.
These findings all do wonders for debunking the myths that boulevards are bad for connectivity. Given the serious cost savings, and quality of life improvements, a boulevard is beginning to look like a no-brainer!
-------------------------------------Original Letter from PWC-------------------------------------------
At the viaduct stakeholder meeting last Thursday, project officials presented the results of how well the various viaduct replacement options will provide mobility. The stunning news -- which we all suspected all along: All options serve the expected demand for trips effectively, only varying +/- 1% comparatively in how many trips they serve. The streets/ transit options work!
The modeling looked at the whole integrated system of travel into, within, and through the city. It tested improvements to the larger system (options A, B, and C) against highway replacement options. Results revealed that if people are offered lots of choices – a variety of streets, transit options, I-5, biking, etc – and connections are improved between urban centers, trips will distribute efficiently and we can all get where we're going.
There are of course variations in how trips are distributed, and particular details about routings and travel times worth examining in more detail (see below.) But first, some remarkable conclusions that emerged from the analysis:
• If all the options serve mobility, why would we even consider suffering the disruption, expense, and risk of a highway megaproject – especially when people are driving less and less?
• If all the options serve mobility in the future, then achieving the win-win-win of a great highway-free civic waterfront, mobility and access for Seattle, and increased attractiveness of downtown as a place to work, live, shop and play is completely within our reach. We don’t need a waterfront highway. Given the clarion call to reorganize our prosperity around lower fossil fuel consumption, we'll be better off without it in some profound ways.
If you want more gory details of the modeling results, read on. Or check out the data yourself at www.alaskanwayviaduct.org.
But first, a caveat about assumptions: the model assumed a 20% increase in trips between now and 2015.
• Despite empirical evidence that driving is declining, and despite solid analysis predicting economic changes and societal interest in reducing emissions could further accelerate reduction in car travel, the model assumed trips continue to grow with population growth.
• The model assumed gas prices remain at around $4/gallon in 2008 dollars, despite many predictions that fuel prices may rise faster than inflation and further decrease our appetite for car travel.
• The state has committed to reducing Vehicle Miles Traveled by 50% by 2050 as part of our shared responsibility to reduce greenhouse gas emissions. However, the model ignores this commitment in its assumption that trips will continue to increase.
• Overestimating demand tends to inflate predictions of congestion and travel times.
What everyone was worried about: traffic flow on I-5
• All options show increased ability to add trips to I-5 compared to today.
• Results show the number of trips diverted to I-5 is pretty low, and the viaduct decision doesn't affect I-5 much; I-5 is pretty full now and will continue to stay full. Options B and C do not increase congestion or travel times on I-5.
• With the options that add a northbound lane on I-5 thru the city (B and C especially), I-5 can serve 4,000 to 5,000 more trips at the PM peak hour. (+7% to 10% increase over current)
• Only 15% of the viaduct trips are long-distance trips bypassing Seattle. The additional capacity created on I-5 coincidentally matches the number of regional trips expected to shift from SR-99 with Options B and C. If the I-5 improvements are done with B or C, there is room for adding the viaduct's regional trips to I-5.
• All the proposed I-5 improvements – lane management, adaptive traffic management, adding a northbound lane – together can increase reliability and flow up to 10% over current capacity.
• When lightrail opens to Northgate, this will free up room for 40,000 more car or truck trips on I-5.
What about freight mobility?
• While freight trips are important, the number of them on the viaduct is fairly low -- 4,000 or 5,000. (To put this in context, the model is dealing with about 2,000,000 total daily trips in the study area.)
• Regional freight trips: Like car trips, only about 15% of these 5,000 trips are regional trips bypassing Seattle and the rest are into or around the city. Regional freight trips can be served by I-5 improvements -- there is capacity there for the low number of trips, and travel times are fairly consistent with today’s times.
• Port's long-distance trips: The Port’s needs for container movement east - west are met by all the options similarly because the projects improving access to container yards are already underway. The travel times to and from highways are about the same across all options.
• Local freight / distribution: With options A, B, and C, local freight trips can use I-5 with similar travel times as today, or they can use Alaskan Way surface street. Travel times are predicted to be higher than today if they choose the surface street. This is partially due to lower speed limits and traffic lights. However, travel time predictions may be inaccurate due to overestimating demand and congestion – see above.
• Additional solutions (freight priority lanes, more demand management for SOV trips, more transit) should be tested to increase speed and reliability of freight trips on Alaskan Way Surface street with options A, B, and C.
• For car trips using the waterfront street, travel times are expected to be 2-4 minutes longer for West Seattle with options A, B, and C than the highway options.
• Transit travel times are pretty consistent across the options. More and better transit service would help West Seattle, and should be pursued.
So for those of you waiting for the technical analysis to confirm the streets/ transit options work, the results are solid. Even by the flawed and probably unrealistic standard of planning for a future where trips increase by 20% in the next 7 years. While there are still some decisions needed to optimize the solution, there is ample opportunity to refine the streets /transit approach to serve mobility and access far into Seattle’s future.
Expect more news on the rest of the evaluation process over the next two weeks. In the meantime, please help spread the good word. Call or email if you have questions -- or if you'd like to donate money to support the outreach and advocacy we're doing!
Cary Moon and Julie Parrett
Co-founders, People’s Waterfront Coalition
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