Improving traffic flow by Whole Foods

Regarding traffic issues around the plaza and WF, I think the biggest problem there is the slow throughput caused by the hard right turn at Main Street. I think we should explore easing that corner (ie removing the "point") to improve traffic flow:

https://www.WaccoBB.net/forums/wacco...3_19-22-03.png

Of course, the sidewalk, crosswalks and signal would need to be re-relocated. The WF cross walk, Laguna Parkway, and the South East crosswalk also interrupt traffic, but if traffic could flow more easily when it is time for it to flow, I think it would help alot.

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Posted in reply to the post by Barry:

...Regarding traffic issues around the plaza and WF, I think the biggest problem there is the slow throughput caused by the hard right turn at Main Street. I think we should explore easing that corner (ie removing the "point") to improve traffic flow.

Of course, the sidewalk, crosswalks and signal would need to be re-relocated. The WF cross walk, Laguna Parkway, and the South East crosswalk also interrupt traffic, but if traffic could flow more easily when it is time for it to flow, I think it would help alot.

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Barry, I think that's probably a lot of money to invest for "...I think it would help a lot".

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Posted in reply to the post by luke32:

Barry, I think that's probably a lot of money to invest for "...I think it would help a lot".

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I think it's worth a study to get a sense of how much it would help and what it would cost. Being that it's a state highway, maybe the state would help out. John, you got any comments about this??

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Posted in reply to the post by Barry:

I think it's worth a study to get a sense of how much it would help and what it would cost. Being that it's a state highway, maybe the state would help out. John, you got any comments about this??

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I think that this would be a terrible idea. As it is, the right-turning traffic sometimes races the yellow (or red) light to make the turn, despite the crosswalk. Also, some people seem to be confused by the signal- do I have to wait for a green right turn arrow? Is a right turn after stopping on a red light allowed? Next you have to add in all of the drivers who turn left on to McKinley from Petaluma Avenue (in front of Whole Foods) who are either inadvertently or intentionally in the left lane to get a few cars ahead, who then have to quickly merge into the right lane prior to the right turn. Finally, you have a conflict point with southbound traffic on Main Street turning left into the Whole Foods parking lot, just after cars have completed their right turn, with this point being not easily visible to cars approaching the right turn from McKinley on to northbound Main Street. Oftentimes, due to congestion in the parking lot, these cars get stuck blocking the lane, bringing traffic to a halt.

I am not a traffic engineer, but modifying the curve at this location would likely result in higher speeds for turning vehicles, to the detriment of pedestrian/bicyclist safety (which is paramount over the needs of cars in my view). I believe that we should do everything that we can to slow traffic down in our urban core, so that higher speed "pass-through" traffic (as opposed to local traffic) gives up in frustration and finds another way. I realize that for many, there may not be other options than going through our downtown. Slowing traffic down would include a return to two-way streets, with a single traffic lane in each direction on Main Street and Petaluma Avenue (with a landscaped center median with left turn pockets on Main Street). Petaluma put their main downtown street on a "road diet", with one lane each way, in place of crammed in dual lanes in each direction. It is now a much more pleasant place to walk, shop, dine, ride your bike and hang out. And, yes, it is a bit slower- big deal. Oftentimes, existing traffic volumes are maintained. Businesses may actually benefit, as the environment is more inviting for pedestrians, shoppers and diners.

When I was on the City Council, there was talk that Caltrans was willing to cede Main Street back to the city in exchange for re-designating Petaluma Blvd. as Highway 116, which would automatically cause Petaluma Blvd. to revert to two way traffic (it would essentially become a north/south bypass for downtown). The city could then convert Main Street to two way traffic. The cost to the city was projected to be huge- about a million dollars, we were told (which is close to the projected cost of the bike lanes on the highways, which are now being provided, for the most part, by Caltrans).

There have been many other proposals- with a two way traffic Main Street, closing Petaluma Blvd. between Highway 12 and McKinley, which would allow the plaza to extend to the proposed hotel site. McKinley would continue to be a through two way street, and cars wanting to go north would turn left on to Highway 12 from Petaluma Ave. to Main Street, then turn right (or just travel north on Main Street). A traffic signal or a roundabout have also been proposed for the intersection of Petaluma Ave. and McKinley.

I have attached two videos. The first concerns itself with road diets. Watch between 1:43 and 1:54 and imagine that same transformation taking place on our Main Street. The second video, while primarily concerned with roundabouts, depicts the transformation of a street similar in size to Main Street. Again, imagine the change in the feel of our downtown if we were able to accomplish a similar "makeover". Finally, I have attached a diagram of what a road diet looks like, as well as some photos of Sebastopol "back in the day".

Just food for thought...

https://vimeo.com/21903160

https://www.youtube.com/watch?v=8bRBtXTJS0I

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Posted in reply to the post by John Eder:

I think that this would be a terrible idea. ...

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Thanks for your support, John! :wink:

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Posted in reply to the post by John Eder:

...I am not a traffic engineer, but modifying the curve at this location would likely result in higher speeds for turning vehicles, to the detriment of pedestrian/bicyclist safety (which is paramount over the needs of cars in my view). ...

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Easing the corner would allow cars to travel closer to the speed limit, as they would on a straight road downtown. But your other points are well taken, particularly the conflict with the left turn into the Whole Foods Parking lot from Main Street.

Given all of the potential conflict areas (multiple crosswalks, turning cars, merging cars, driveways, drivers with their heads up their phone, confused tourists, large trucks, jaywalkers, spaced-out residents, etc.) in the transition zone from northbound Petaluma Avenue to northbound Main Street (past Whole Foods), the need is not for speed, but for safety. Traffic should never exceed 25 MPH in our urban core, in my opinion, with even lower speeds preferred. Save your high speed driving for westbound Highway 12 at 5:30 PM...

From the "Urban Street Design Guide" See: https://nacto.org/publication/urban-.../corner-radii/

Corner Radii

Corner radii directly impact vehicle turning speeds and pedestrian crossing distances. Minimizing the size of a corner radius is critical to creating compact intersections with safe turning speeds. While standard curb radii are 10–15 feet, many cities use corner radii as small as 2 feet.

In urban settings, smaller corner radii are preferred and actual corner radii exceeding 15 feet should be the exception.

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A large corner radius should not be used to facilitate a truck turning from the right lane into the right lane.

The size of the corner relates directly to the length of the crosswalk. Longer crosswalks take more time to cross, increasing pedestrian exposure risk and diminishing safety.

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A smaller curb radius expands the pedestrian area, allowing for better pedestrian ramp alignment.

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The distinction between the corner radius and the effective turning radius is crucial and often overlooked. The corner radius may be a simple or a complex curve and depends primarily on the presence of on-street parking, bike lanes, the number of travel lanes, medians, and traffic control devices.

Designers often determine corner radii based on the intersection geometry only and overlook the effective radius. As a result, drivers making a turn on a green signal have little incentive to turn into the nearest receiving lane and routinely turn as wide as possible to maintain travel speeds.

Effective turning radius:
https://nacto.org/wp-content/themes/...ing-radius.png


Recommended

Turning speeds should be limited to 15 mph or less. Minimizing turning speeds is crucial to pedestrian safety, as corners are where drivers are most likely to encounter pedestrians crossing in the crosswalk.

Turning Speed Formula:

https://www.WaccoBB.net/forums/wacco...5_16-56-18.png

Radius Reference Chart:
https://www.WaccoBB.net/forums/wacco...5_16-57-10.png

It may be good to keep the hard right, as it slows traffic down … which is a good thing in my book. The hard right also calls attention to the traffic light, & the pedestrian walkway.

You want to speed up traffic for drivers passing through downtown Sebastopol. That that would be a bad idea for pedestrians. It's already dangerous enough even if you carefully use the crosswalks like I do. Also faster traffic might attract more through traffic without benefiting residents or businesses in any way. Drivers should just try to relax and practice equanimity for a few minutes. When I feel impatient sometimes I think about the people who are trying to go from Syria to Europe.

Barry, I think the biggest issue with WF is that they don't have designated entrance and exits for the parking lot. What would help traffic on McKinley would be an entry only from McKinley and exit only Right turn only onto Main.

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Posted in reply to the post by Barry:

Regarding traffic issues around the plaza and WF, I think the biggest problem there is the slow throughput caused by the hard right turn at Main Street.

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