If the ?road diet? project on Petaluma Boulevard North could be compared to a weight-loss commercial, then it?s nearly time for the ?after? shot.
New pavement and lane striping is complete, along with wider curb parking, new sidewalks and streetlights on the stretch between Washington and Lakeville streets.
Only a few cosmetic changes remain ? activation of flashing crosswalk lights at two locations and new traffic-signal timing at the main intersection.
The new signal poles are already in and should be active in a few weeks, after electrical work is checked to ensure the signalization works properly, said Larry Zimmer, the city?s capital improvements manager.
That will bring an end to the long-planned project, a $2.2 million reconfiguration of the four-lane road segment into three lanes ? a wider travel lane in each direction and a dual left-turn lane in the center.
With a center turn lane, traffic won?t back up behind a driver trying to make a left onto a side street or driveway, officials said ? that driver can now move into the center lane and wait for one lane of oncoming traffic to clear, rather than two.
In addition, the wider parking areas along each curb give drivers the ability to park without pulling their right wheels onto the sidewalk.
Combined with the wider traffic lanes, passing drivers won?t have such a narrow space between their cars and those parked along the curb, which caused many to slow to a crawl in order to safely navigate the precarious stretch of road, the city said.
At the intersection, the new signals will improve traffic flow by monitoring traffic patterns more closely, said Frank Penry, the city?s traffic engineer.
Previously, drivers heading north or south on the Boulevard crossed the intersection at the same time as others turning left from the same direction.
There was no dedicated left-turn-only lane, so cars waiting to go straight through the intersection sometimes sat and stacked up at a red light even when none of the opposing traffic made a left in front of them.
Now, with the addition of left-turn lanes and smarter traffic signals, north and south traffic will flow at the same time, Penry said.
If no cars are coming in one of those directions, the system is smart enough to switch on the green arrow for the opposing left-turn drivers to let them proceed.
Likewise, if no left-turn drivers are at the intersection, the system will recognize that and give the green light for opposing through traffic, he said.
?It allows us to be more adaptive to traffic situations,? Penry said.
On the other side of town, half of the South McDowell Boulevard road diet has been completed for some time.
As on Petaluma Boulevard, a single lane in each direction will be created, with a dual left-turn lane down the center.
Six-foot bike lanes and eight-foot shoulders for curb parking are being built.
The changes will act as a ?calming effect? to reduce speeds and collisions in the area, the city said. Neighbors whose homes open onto South McDowell urged the City Council to enact the changes last year, saying large trucks barrel down the four-lane street as a shortcut from Lakeville Highway.
The segment from Weaverly Drive to Baywood Drive was finished last year and work on a roundabout-style intersection at Baywood began. But construction stalled last fall after the city realized more money would be needed for the project.
How to participate
A coalition called Protect the Pacific is organizing a bus trip from Sonoma County to Sacramento for Thursday’s rally. For information, click here. Buses are also going from San Francisco, Oakland and Ventura.