Blogging Bayport Alameda

July 2, 2014

Spin me right round

Filed under: Alameda — Lauren Do @ 6:02 am

I don’t often drive on the East End, but I did the other day down Fernside and it struck me that a few of the intersections might be better served by having a roundabout as opposed to the full four-way stop that currently exists.   The one I’m think of is Central at Fernside.  Perhaps at other times there are more people trying to cross Fernside from Central, but it seemed that it was mostly the Fernside traffic that had to make halfhearted stops because the stop sign was present.  Some people even used the old Hollywood Stop — as an aside by husband calls this a California Roll, I’m not sure which is correct, but I digress.   A roundabout would move the traffic along more efficiently.  I think there are a few intersections on Bay Farm that probably would benefit from a roundabout as well.

Someone on Facebook posted this video from the old Mythbusters gang as they attempted to figure out if an intersection moved more cars though or if a roundabout was better.   I really enjoyed it because I really didn’t know if one was technically more effective than others.  If you have 10 minutes, give it a watch:

The takeaway if you didn’t watch is that the roundabout moved more cars through the intersection in the same amount of time.   A commenter to the Facebook post noted that American drivers aren’t typically accustomed to driving in roundabouts so it actually might be slower.   According to the Mythbusters test though it didn’t take the test drivers that long to get used to the new system.   Although some people still don’t understand the concept based on my observations around the Bayport roundabouts.

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27 Comments

  1. The stop sign at Central, as well as the one on Garfield, helps keep the traffic speed reasonable for the residents of that stretch and facilitates crossing Fernside for the large number of families & kids that use Lincoln Park.

    Fernside already has a significant speeding problem. If you want to witness this first hand, drive 25MPH down Fernside during commute time. You’ll be tailgated consistently. Glance in the rear view mirror & you’ll see some angry, frustrated looks and what appears to be lip-synched profanity. Taking out the stop signs would turn it into a freeway.

    Comment by dave — July 2, 2014 @ 6:19 am

  2. Note also that a large number of students use those stop signs for safe crossing to & from Lincoln Middle School.

    Comment by dave — July 2, 2014 @ 6:28 am

  3. There was a reference somewhere that said that roundabouts are safer for pedestrian crossings. I don’t know if this true or not because it seems like it would be the opposite (yields only and such).

    Comment by Lauren Do — July 2, 2014 @ 6:37 am

  4. How do you want your kids to cross, at a stop sign or a roundabout?

    Comment by dave — July 2, 2014 @ 6:56 am

  5. I would first consult those who live right there. They’ll have to live with it every day.

    Comment by Joe — July 2, 2014 @ 7:30 am

  6. They cross at a roundabout almost daily when walking to school.

    Comment by Lauren Do — July 2, 2014 @ 7:31 am

  7. Spend a school day from 7:45 to 8:30 along that stretch and then come back with your answer.

    Comment by dave — July 2, 2014 @ 7:38 am

  8. I live at that intersection. Dave is right about the speeding. It’s the same issue as Lincoln — long stretches of uninterrupted street lead to speeding. The APD is often parked in front of my house on Central pulling over those who run/roll through that stop sign.

    For pedestrian traffic to LIncoln Middle, there is a full light at Encinal and Fernside, which would probably be sufficient. But between Central & Garfield is the rear entrance to Lincoln Park which does also have a fairly significant amount of family pedestrian use, especially on soccer/softball/baseball days.

    It’s an interesting question, if moot b/c I don’t think the four corner house owners there would want to give up any of their small front yards for a roundabout.

    Comment by Matt Parker — July 2, 2014 @ 8:08 am

  9. Also not sure if the intersection in question is really comparable to what is in Bayport. There must be significantly heavier traffic on Fernside and I would assume there is a bigger problem with speeders there too.

    Comment by Joe — July 2, 2014 @ 8:13 am

  10. 9

    Yes. Obviously.

    Comment by dave — July 2, 2014 @ 8:18 am

  11. never heard of Hollywood, but California roll like the Sushi yeah. Berkeley has a lot of street diversion which can be maddening if you hit a complete barrier, but they have sort of round about things at small intersections. I think most have stop signs too in at least one direction. The real round about is at the bottom of Marin as it comes off the hill and it has about four other streets which feed in at weird angles. I’ve seldom approached heavy traffic where I didn’t have to stop for safety just to spot an opening. It is surely better than four way, but can be intimidating and it helps to be assertive. Even with hesitant drivers or those who simply barge in obliviously I’ve never seen an accident. It seems to me the scale is somehow important when it comes to pedestrians. If the round about is a small intersection it could be more of a liability, but that’s just my notion.

    Comment by MI — July 2, 2014 @ 8:38 am

  12. There is a roundabout in Berkeley I’m familiar with but it’s at a much more complicated intersection with several streets coming together at once. They are pretty uncommon around these parts and I’ve noticed people who aren’t used to them don’t know what to do and navigate them clumsily. They are also very expensive to build. You’d have to have a much more compelling reason to build one at Fernside and Central.

    Comment by Denise Shelton — July 2, 2014 @ 8:38 am

  13. I have lived in Paris where roundabouts are heavily used and I have traveled in areas like upstate New York and Long Beach where roundabouts are used. Thought they are more efficient in getting more cars through the intersections, they can be dangerous. The designer of the Long Beach roundabout was killed in a car accident using the roundabout, as was his sone a number of years later. The navigation required around the Arch of Triumph in Paris was as difficult as it could be. You took your life in your hands each time you used it. Scotland uses them as well and the drivers there are far more patient, thus much easier to drive through. Given the inability of some nationalities to navigate their vehicles correctly, I would be concerned if roundabouts were to be used here.

    Comment by Bill — July 2, 2014 @ 8:42 am

  14. Here’s the study about roundabouts that I had mentioned earlier, excerpt:

    The results indicate that intersections that had minor and medium levels of traffic volumes roundabouts were generally safer than the intersections that were stop controlled and signalized. However, high volume intersections with signalized traffic controls appeared to be safer than the corresponding candidate roundabouts. But, the results for the high volume intersections were statistically not significant.

    The study goes on to note that crashes were less frequent because there are 75% less “conflict points” than a traditional intersection.

    Comment by Lauren Do — July 2, 2014 @ 9:05 am

  15. If there was a comprehensive traffic calming plan for fernside from bridge to bridge, you might be able to sell roundabouts. If there was a big road diet, pedestrian bulbs, etc, designed to bring average speeds down to 20 mph, then roundabouts to move more cars through the intersections could work. That street is wide, and most people driving it don’t live right there, so they just want to jam through. Slow and moving the whole time is better than the floor it and slam on the brakes method that dominates now. It would also lower everyone’s blood pressure not to have to queue at the stop signswhen there is little cross traffic, but rather calmly rolling through the intersections.

    Comment by BMac — July 2, 2014 @ 9:50 am

  16. If all we care about is traffic flow, just remove the stop signs and put up Jersey walls and call the Fernside Freeway.

    But it is a residential neighborhood with a popular park and a 900+ student school. I thought we cared about pedestrians & walkability.

    Comment by dave — July 2, 2014 @ 10:16 am

  17. to be clear, there seems to be a volume limit to round abouts being effective. They have them in Boston don’t they? I’ve only been a car passenger there once forty years ago but I know the driving there is “legendary”. I recall being given a thrill merging in and out of traffic free for all. It’s not like all the conditions can be easily met, but the comment 15 makes a lot of sense, dave. Other than the shopping districts and shopping mall areas, all of Alameda is essentially residential which is why we have 25 mph speed limit, right?. Imagine living on 900 block of Park between Clinton and Otis. When I signal 1 block in advance and slow to turn right on Clinton off South bound Park street I still have some idiot driving right up my ass so they can get to the stop light at Otis 1/2 second faster. Texting peds with ibuds in their ears crossing at Clinton seldom look over their left shoulder, just step into the abyss. Slow and steady wins the race, so I’m all for “comprehensive road diet” where it can meet that end. Fernside is wide and lines of sight are good, compared to Park where two lanes merge after San Jose. People actually speed up at that bottle neck to get in front of one another, one short block from Clinton. Nuts.

    Comment by MI — July 2, 2014 @ 10:57 am

  18. In several ways, roundabouts are safer than 4 way stops.
    see: http://safety.fhwa.dot.gov/intersection/resources/needsidrpt/sect01.cfm

    Namely, roundabouts have 8 “conflict” points vs. 32 for a 4 way stop.

    “Because traffic enters and exits the roundabout using only right turns, the number and types of hazardous traffic conflicts are lessened. The exposure for severe angle crashes is substantially reduced. All approaching vehicles are required to yield to vehicles already in the circulatory roadway, so rear-end crashes from vehicles stopping suddenly are much less common.
    However, pedestrian crossings are potentially more challenging because entering traffic does not have to stop if there are sufficient gaps. On the other hand, pedestrians have a lower risk of being involved in a severe crash because of the lower vehicle speeds and having to cross only one roadway at a time.”

    In the case of Fernside & Central, I agree with BMac #15: if roundabouts were in place along with a comprehensive traffic calming plan bridge to bridge, the roundabouts would be safe for pedestrians.

    Note that a 4 way stop in no way guarantees safety for pedestrians. So many times, I have made a move to cross a 4 way stop intersection, only to have a car roll through the stop in front of me or stop beyond the limit line with no regard to a pedestrian in the crosswalk. I think that this rolling through stop sign behavior is actually more dangerous because the pedestrian is making moves assuming the car will stop completely at the limit line. With the roundabouts the pedestrian has an expectation that the cars are supposed to give pedestrians the right of way but may not. A pedestrian compensates for this by verifying the safety before entering the intersection.

    Comment by AJ — July 2, 2014 @ 11:09 am

  19. With the roundabouts the pedestrian has an expectation that the cars are supposed to give pedestrians the right of way but may not. A pedestrian compensates for this by verifying the safety before entering the intersection.

    ——————————————————————————————————————–

    And that’s different from other intersections how?

    Comment by dave — July 2, 2014 @ 11:18 am

  20. There is a difference. In a 4 way stop one has an expectation that the car will stop, with a roundabout one doesn’t. It’s a big mindset difference. We should verify full stop at a stop sign before crossing but often we don’t based on the expectation. With a roundabout one does not have the expectation of vehicle stop and one behaves differently.

    Comment by AJ — July 2, 2014 @ 11:38 am

  21. For the current traffic volume, I think the existing intersection configurations are OK. Adding a signal light at Central might enhance ped safety, but I doubt that the traffic or collision stats would meet the state standards (warrants) for installing one…

    Comment by Jon Spangler — July 2, 2014 @ 1:17 pm

  22. since a roundabout is round and has a hub planted in the center of the intersection for directing traffic, can the current square intersection accommodate that reconfiguration without having major sidewalk and street modifications? just as huge roundabouts are potentially dangerous, is there a point where they are too small? For those who don’t know it, the Marin Circle in North Berkeley is pretty big compared to the average four way intersection, which allows it to function safely.

    Since I don’t need to be there I avoid that intersection when students flood the street. On Oak St at Alameda Avenue it can get crazy when Alameda High lunch lets out and at 3 pm. It is a T intersection with no stops for Oak Street, not four way stop, and traffic off Alameda Avenue onto Oak is comparatively light, or it would get really unbearable for drivers. Without a light, are cars held for inordinate amounts of time as kids at Central and Fernside flood to and from Lincoln school?

    Comment by MI — July 2, 2014 @ 3:37 pm

  23. 14. the link to the study didn’t work from this computer. 18, at a glance I didn’t quickly identify stats for peds. Side bars for bikes and peds were general, not specific to roundabouts.

    I just watched the Mythbuster video and had an epiphany about peds. They didn’t have any in their video! I had visualized peds checking for traffic entering, but not dealing with vehicles exiting the flow. The elevated camera angle in the video made me think that if the circle were small enough there might be cars attempting to exit stopping flow in the circle when they yield for peds. In my mind, throwing bikes into the mix brings up other issues of cars trying to shoe horn past slightly slower bikes in a short distance. Interesting to challenge ones perceptions. I’d like to see a similar video of a controlled study which addressed all factors, peds, bikes and scale of roundabouts.

    Comment by MI — July 2, 2014 @ 4:15 pm

  24. No mention of bikes??

    Comment by flow — July 2, 2014 @ 11:34 pm

  25. oops! @23 bikes were mentioned

    Comment by flow — July 2, 2014 @ 11:36 pm

  26. want to be helpful and be specific, or just glib? My computer didn’t connect with Lauren’s link #14. Scanning the page that pops up in link from #18 there was no mention of bikes I saw. Clicking the couple of side bar links for bikes and peds also didn’t find specifics for roundabouts, did you?

    Comment by MI — July 3, 2014 @ 7:38 am

  27. France use roundabouts extensively , why ? so traffic does not stop …… is it safer for pedestrian ? no because the driver has limited visibility and the crosswalk is located where the old stop sign used to be , one difference traffic does not stop . Just last week one young mother was hit and Her 18 months old baby killed .
    Good luck riding a bike , but then they do not stop at red light or stop sign either .
    American still have to find their way out of them, Lauren if you like Berkeley So much , they have houses for sale , in the mean time we like Alameda with all it’s Defects …Perfection is an utopia .

    Comment by Get a traffic engineer degree — July 3, 2014 @ 2:59 pm


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