Rainier connector may not open until 2020
Latest studies of interchange project show cost of at least $75 million
Published: Thursday, May 8, 2008
By COREY YOUNG
ARGUS-COURIER STAFF
There was good news and bad news about the Rainier Avenue crosstown connector and interchange project for Petaluma City Council members Monday.
While the latest report says the addition of Rainier will reduce travel times for drivers on other crosstown routes in the future — and won’t have a negative impact on the flow of freeway traffic — the cost of the interchange and roadway has risen to a minimum of $75 million, and it might not open for 12 years.
The city’s preliminary schedule says construction could begin as soon as 2012, but the fact that the completion of Rainier depends on the as-yet-unfunded widening of Highway 101 through Petaluma means there is uncertainty over when the project will actually be completed.
The portion of the Marin-Sonoma Narrows on Highway 101 within city limits has an estimated cost of $165 million, with only $35 million currently set aside.
The segment of the freeway that rises over the railroad tracks in central Petaluma needs to be lengthened so there is room for the Rainier extension to pass underneath, officials said.
Although there is uncertainty over the construction timetable for Rainier, the city is getting ready to submit its draft Project Study Report to Caltrans, a key step in advancing work on the project.
The report examines how the Rainier project would affect traffic congestion on local streets and the freeway, in addition to estimating the cost of five design alternatives for the project.
Those alternatives range from “no build,” or canceling the project, to three variations of a traditional diamond interchange as well as a “crosstown connector-only” proposal with no ramps connecting to the freeway.
Updated cost estimates for each alternative were presented at Monday’s meeting, with the cheapest option — other than doing nothing — being the connector-only road, at $38 million.
Building a diamond interchange with a loop ramp in the southeast quadrant would cost $75 million, while a “tight diamond” interchange would be $78 million, the report said.
Combining the East Washington and Rainier onramps and offramps via a system of frontage roads parallel to the freeway is the most expensive option, at $109 million.
That plan was created as a way to avoid the less-than-one-mile spacing between the East Washington interchange and the proposed Rainier interchange. The city is asking Caltrans to waive the typical one-mile-apart requirement for interchanges if auxiliary freeway lanes are built between the two points.
The cost estimates include project design, acquiring property for right-of-way and building the project, said Vince Marengo, Petaluma’s public works director.
A breakdown of each alternative’s cost shows that the project would be funded from three main sources: Traffic impact fees on new development, the construction of roadway segments by developers of adjacent property and $10 million in redevelopment money already approved by the council.
New estimates in the report presented Monday show Rainier would benefit drivers on other crosstown routes and some freeway traffic, while adding “no discernible change” to rush-hour traffic on Highway 101.
Without Rainier, by the year 2040 it would take drivers 14 minutes to travel along East Washington Street from Ellis Street to the McDowell intersection during the morning rush hour.
However, the creation of an interchange at Rainier could lower that time to about three minutes, said Eddie Barrios of Fehr & Peers, the city’s traffic consultant.
The same route traveled in the afternoon could take more than 10 minutes in 2040 if Rainier isn’t built, Barrios said. With a Rainier interchange completed, that time is shortened to about 21⁄2 minutes.
“We are alleviating quite a bit of traffic congestion at the East Washington interchange, not only under current conditions but also in the future,” Barrios told the council.
“The traffic volumes will be lower if you build an intersection than if you did nothing,” he said.
“Obviously, ‘no build’ is not an option,” Councilmember Mike Harris said after hearing the traffic projections.
While the addition of a Rainier interchange would cause “no discernible change” in freeway flow during the morning and afternoon rush hour, it would ease congestion for drivers heading north in the mornings and south in the evenings, Barrios said.
Without Rainier, by the year 2040 the average travel time from Railroad Avenue in Cotati to Kastania Road south of Petaluma would be 11 minutes, 19 seconds for southbound afternoon drivers, Barrios said.
With any type of interchange at Rainier, that time could be cut by 39 percent — to about seven minutes, he said. “It’s a dramatic difference,” Barrios said.
Part of the reason for the longer travel time under the “no build” option by 2040 is that without Rainier, vehicles getting off the freeway at East Washington Street would begin stacking up so far that the line would stretch into the freeway lane, causing freeway traffic to slow down, Barrios said.
The city plans to submit its draft Project Study Report to Caltrans at the beginning of June, Marengo said. Officials will request an “expedited” review process in hopes of approving the final PSR in August, he said.
Once the PSR is completed, the next step is to begin environmental studies and select one of the interchange design alternatives, he told the council.
(Contact Corey Young at corey.young@arguscourier.com)
