Local government elected officials and their staffs in the central Puget Sound region have worked over the past two years developing a transportation taxation and spending package for highway improvement that is part of the November 6, 2007 election package called "Roads & Transit -- Proposition 1."
The contemplated Roads & Transit new construction spending of $47 billion (including bond interest) is split into $31 billion for the Sound Transit regional transit planning and construction agency, and $16 billion for the Regional Transportation Investment District (RTID) the part for highways. If the measure passes, RTID will become a new funding agency using $80 per $10,000 value motor vehicle excise tax and 1/10 percent sales tax to supplement the gasoline tax collections that fund the Washington State Department of Transportation (WSDOT). Sound Transit's expansion funding, mostly for light rail construction, would come from 5/10th percent new sales tax on top of the 4/10th percent sales tax already collected for Sound Transit's start up program underway since 1997.
Computer modeling of the traffic performance changes estimated to occur with the Roads & Transit package have been carried out by WSDOT staff. The computerized traffic model made a comparison between two forecasts of future traffic in the three-county region, one for 2028 with Roads & Transit built and in operation, and another forecast without Roads & Transit. The comparison showed that afternoon peak traffic delay would be 18% less bad in 2028 with Roads & Transit implemented, compared to 2028 traffic without Roads & Transit. Still, afternoon traffic delay is forecast to increase either way from today's conditions -- by 118% (more than double) without R&T, or by 79% with R&T.
This graphic illustrates the computer modeling:
The region-wide average daily weekday forecast of travel delay hours were calculated as follows:
| Year of average weekday modeled conditions |
2006 |
2028 forecast |
2028 forecast |
| Modeled scenario includes | What is open and operating in 2006. | Completion of the two recent WSDOT gas tax investments and also Sound Transit light rail from SeaTac Airport to Husky Stadium and commuter rail from Lakewood to Everett. | All the projects completed in the previous column, and in addition the $47 billion Roads & Transit projects, including light rail from Lynnwood to Tacoma via downtown Seattle, with a branch across Lake Washington to downtown Bellevue. |
|
Daily hours of delay in the PM peak period |
106,582 |
231,960 |
191,290 |
|
How much worse is the 2028 PM peak period delay compared to 2006 conditions. |
118% |
79% |
|
|
How much less bad would the PM peak period delay be in 2028 as a result of Roads & Transit. |
18% |
Source: Hours of delay from table at bottom of
page 24 of October 10, 2007 State
Audit, WSDOT
Management and Improvement to the State Highway System for Maximum Throughput
and Minimal Congestion.
Interpretation of those numbers from personal
conversation with WSDOT modelers.
NOTE: On October 10 2007, RTID staff provided PTIF with a document that provided further information on WSDOT's modeling, posted in PDF here.
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