Silly Straws

Use Physics, Not Plastic, for Safety

I was told by an SFMTA official that there is no way to stop a motorist who is so reckless that they'll blow red lights and go 100 mph on city streets. Too many engineers and planners don't get that their street designs are what make reckless driving possible in the first place. Most of San Francisco's streets are so wide and straight that speeding is not just possible, it's almost encouraged.

But imagine driving 100 mph through this intersection in Paris:

It doesn't matter if you're Mario Andretti or Mr. Magoo, go much faster than 20 and you will hit a pole or a tree. Steel poles and the traffic cop of physics make it impossible to speed. Those poles were added specifically to force drivers to slow down as they navigate between Rue Lamark and Rue Caulaincourt.

Using physical obstacles to narrow lanes, tighten turns, control speeds, and stop encroachments is understood in the Bay Area on some level. But instead of steel, the city relies on "silly straws," better known as safe-hit posts, to encourage motorists to slow down and stay in their lane.

I've watched cars drive over entire blocks worth of safe-hit posts. It's such a common problem, the SFMTA couldn't even manage to find a picture for its Tenderloin safety project web page that didn't include a broken safe-hit post:

I've asked, multiple times, why the SFMTA continues to use plastic straws instead of steel or concrete to force motorists to slow down and stay in their lanes. It's not that K-rails, steel posts, and concrete planters are prohibitively expensive or difficult to install. I was told on the q.t. that the city just doesn't want the liability from its installations smashing up people's cars.

Previously, previously, previously, previously, previously, previously.

Tags: , ,

34 Responses:

  1. Nathan Williams says:

    You don't even need to make all of them steel! Just make, say, one in twenty a steel post (admittedly more work to install) covered with a silly straw, and let drivers know that they're taking their chances when they decide to try to run one over.

    • jwz says:

      As always, I favor mandating that all driver-side airbags be replaced with a foot long steel spike pointed at the driver's center of mass. Drivers will really understand "safe stopping distance" if we do that.

      But again, in true Panopticon style, you could probably get away with having a small but significant number of airbag modules swap out the balloon for a mortar. Intermittent reward leads to the best operant conditioning!

  2. Krisjohn says:

    "Traffic calming measures", as described, suck. Speed bumps, chicanes and similar things critically hamper emergency vehicles and should not be used.

    If you really want to slow down a wide, straight street, put parking in the middle of it.

    • Christof says:

      This old argument again.

      Let's pretend there is some truth to it.

      Just make bike lanes wide enough for emergency vehicles.


    • That is false. There is a really good counterexample in the North Fair Oaks neighborhood of unincorporated San Mateo County between Redwood City, Menlo Park, and Atherton. The streets there were long and straight and wide so traffic calming got put in all over the neighborhood with mini traffic circles at four way intersections and a mix of constrictions and chicanes everywhere else. The local fire station is right in the middle of all of this at Fair Oaks and 15th Avenue. Firefighters initially protested but found that after a small amount of practice it is possible to safely navigate traffic devices at speed. When it comes to optimizing emergency responses real experience is the best source of information.

      • Krisjohn says:

        How is that not proof of my point? Are you saying that roads that need special practice are ok? I guess they might be, so long as you're not one of the first few emergencies they use for practice.

        You're all also ignoring that I proposed an alternative solution.

  3. NSI says:

    Admittedly, I'm part of the problem. I was visiting San Fransisco (I stopped by DNA Pizza and bought a slice), meeting up with some friends from Europe. I rented a minivan way larger than what I'm used to driving. Trying to merge on to a freeway the person beside me sped up, so while attempting to squeeze in I choose to blow through an edge of a triangle of those straws, knowing what they were. My European were freaking out, thinking I'd never get my deposit back. They only left a little silver dust on the bumper that wiped right off.

  4. Leonardo Herrera says:

    That "imagine driving 100 mph through this intersection in Paris" phrase immediately made me remember of C'etait un rendez-vous.

    • jwz says:

      When I was a teenager I thought that video was cool. Now I just think that's guy's an asshole.

    • Milt says:

      The sheer logistical issues of filming such a thing in 1976!!! I'll note, tangentially, that I met a series of older gear-heads here in the DC area who talked about timing the beltway just after it was built, at 4am when the cops would've been done for the evening.

  5. Gyyyom says:

    As a french, i can assure you these metal poles are not there to prevent speeeding (traffic takes very good care of that 16hrs/day, thanks). The poles are purely to prevent people from parking (and/or driving) on the sidewalks.

    • Marc Lacoste says:

      Note the picture shows a forbidden way, as it is a one-way in the opposite direction (except bikes, "sauf").
      I know this crossing, my wife has a flat rue Lamarck currently, there are stairs to montmartre right there. When you're a pedestrian, this is a crossing you want to run accross to avoid 70km/h drivers - the limit is 50km/h but most people are over this, and some accelerate way beyond to cross past orange lights.

      Paris is notably easy for car speeding, with large boulevards thanks to Haussmann. A better example would be the netherlands woonerf zones, with no obvious traffic seperation : drivers are subliminaly encouraged to be slow as anything can happen anytime, like a child crossing.
      And some poles are not in metal but often in blubbery plastic, to avoid cracking the street pavement everytime someone bumps into it. Yon won't run over it as it's too hard though.

      Plastic straws are everywhere in Paris right now, as the pandemic led the municipality to believe it was necessary to make some urban adaptations in a haste, to favor extremely poorly designed bike lanes in the center of the street, see it in all its splendor, with a delivery car parked right in the middle:,2.3268258,3a,75y,300.47h,57.17t/data=!3m6!1e1!3m4!1slhZUe56ppvaj63Az-gfY-Q!2e0!7i16384!8i8192

    • Lloyd says:

      Ah, France! Where speeding men kill themselves by driving fast into shady trees that line the roads! And the only way to make the roads safe is to cut all the trees down!

  6. Tcheko says:

    Being french, those steel poles are mostly there to avoid rogue parking on sidewalk. There were not intented for security or speed control measure even if indeed, they can provide some kind of protection for pedestrians. Also, parking slots aren't free in most part of big cities...

  7. Alex Q says:

    An interesting expat, living in the Netherlands, has a youtube channel dedicated to street-design (he's the kind of guy who gets excited about traffic-lights).

    He, over and over, points out that the whole design of long straight roads is just bad and dangerous. Unfortunetely many / most people prefer instant gratification over long term improvement:

  8. tfb says:

    If governments actually cared about speeding they'd simply use ANPR cameras and nick everyone who was speeding (and everyone who drove in a bike lane, &c fc). All of the annoying traffic-calming stuff could just go.

    People will now say 'but that's suveillance'. And it is, and I've eventually realised I'm fine with that: ride a bike, walk, or take public transport if you don't want to be surveilled.

    • Dude says:

      Well... that pro-NSA position notwithstanding, it doesn't address the fact that (in addition to creating a surveillance state) the ANPR system is dodgy at best.

      • jwz says:

        Also dodgy is the notion of "cops will notice people breaking the traffic laws and ticket them, and that will happen with such frequency that people will stop driving like assholes out of fear of retribution."

        Intermittent reward leads to the best operant conditioning!

        • Dude says:

          Seriously! I can't find a single piece of evidence ANPR implementation has actually decreased traffic violations or crimes. All I can find is that governments and private businesses THINK it does, so they'll pay for 600 HD cameras to watch a single bird-feeder (notoriously a major hub of criminal activity).

          • tfb says:

            In the UK, we have sections of motorway which have average speed checks: they check (or claim to) the cars entering and leaving the section, record (again, or claim to) the average speed and nick people (again ...) who are going too fast on average, as 8'm suggesting. I can tell you from very considerable personal experience (I have driven through these sections probably hundreds of times, perhaps more) that they ... work: people stick to within a small number of miles an hour of the limit. I also have driven through at least thousands of signposted-but-seldom-enforced 30MPH zones in towns and villages, and because I actually obey the law and don't speed I have, many times, been hooted at, sworn and occasionally spat at as cars overtake me.

            Having some American tell me what works in this case is kind of similar to having some American tell me that controls on ownership of semiautomatic weapons don't work. Yes, I understand that you have problems about keeping some kind of track of people who choose to own lumps of metal which kill people. That's fine: that's a choice you make. But then shut the fuck up when people kill you with those lumps of metal, why don't you?

            • Dude says:

              So... to review: you're in favour of a surveillance state because your unscientific personal experience - which you admit several times in brackets as being only theoretical hyperbole - is worth sacrificing one's personal freedom to a privately-owned system that's prone to data-breaches? And you're angry...why; because I won't agree that your unscientific, freedom-violating "research" would have the same unproven efficacy in another country with different automobile laws and road designs?

              That about the long and short of it?

              • jwq says:

                That's a silly straw man argument. While it might be ironic in context, as an argument it's not at all persuasive.

        • Doctor Memory says:

          Over here in NYC, some mad genius noticed that traffic violations were public information and put together How's My Driving NYC to let you look up the moving/parking violations of any car license tag.

          You will be utterly unsurprised to find out that several people have taken to regularly running the plates of the personal muscle cars parked in cop lots and by a stunning coincidence they very often have dozens and dozens of automatic speed camera tickets but not a single moving violation written by a human being.

          Amazingly, the NYC city council has actually listened to the complaints on the problem and is right now debating a bill to remove traffic and parking enforcement from the NYPD and give it back to the city DoT. Predictably, our spineless coward of a mayor is against it.

          • Doctor Memory says:

            (As a postscript, an interesting bit of history: the DoT was in charge of traffic enforcement until about 30 years ago when it was awarded to the NYPD (along with "school safety officers") during the Giuliani era. Predictably, the NYPD uses it to fake their diversity numbers: traffic and school "officers" are overwhelmingly nonwhite, often female, and to a first approximation are never ever ever promoted to actual police positions. Writing a speeding/parking ticket on an actual cop's car, or family of a cop's car, is of course a fast path to unemployment.)

  9. Floutsch says:

    Hm... a few days ago a friend and I discussed something similar. The silly straws are exactly that, silly. But I also think that stelle rods might pose a danger to third parties aside from the reckless drivers. My idea would be something like pipe cleaners. They'd just really scratch up your car. In a genuine accident that's probably the least of your concerns and you could even make them flexible enough so that the stand up again after being driven against. THat seems like a nice option where it's unfeasible to change street layout.

  10. Nick Gully says:

    I keep threatening to park two old junker Cadillacs opposite each other on my block to threaten traffic.

    Anyone hitting one of those things is going to shred their jellybean luxobox SUV.

  11. Baloo Uriza says:

    Seems like the obvious answer is to sue the city for allowing a motorist to smash your body.

  12. dcapacitor says:

    The question is, who gives a shit about pedestrians in America? Isn't walking for, like, poor people?

  13. Those plastic tubes are quite fun to ride over when it's not your car or you are not worried about the repair costs.

    Having one lock in your bike because some vehicle tried to use the already small parking space to overtake another not so much.

    Here we mostly have solid (about knee high concrete bumps with steel core and pike) only as decorations

  14. Sam says:

    hahah, i grew up just right on this intersection on rue lamarck in paris, so surprised to see it on your blog jwz!

  • Previously