Help Wanted: Road Curves

I’m muddling through a WCYDWT unit on modeling right now and I’m short on data. If you know of a curve that’s preceded by a recommended speed sign, would you copy the link from Google Maps and paste it into the comments. Obliged.

I'm Dan and this is my blog. I'm a former high school teacher, former graduate student, and current head of teaching at Desmos. More here.


  1. Chris Craft (@crafty184)

    December 17, 2010 - 4:28 pm

    Hi Dan,

    We have a famously horrendous interchange between two major interstates in Columbia, SC. It has earned the nickname “Malfunction Junction” because it is so poorly designed. In fact, many many crashes occur there.

    Here is a link to the beginning of one of the worst curves, going from I26 to I20, where trucks often turn over, hence the warning.


  2. Holly

    December 17, 2010 - 9:04 pm
  3. Rachael

    December 18, 2010 - 12:44 pm

    And one from New Zealand (also in km/h) :-)

  4. Elaine C.

    December 19, 2010 - 9:56 am

    Don’t have the link/time to look it up right now… but if you’re ever near the south(ish) end of Santa Cruz, on the 1, coming into town… there’s that crazy right split where it joins the 17… the ‘Curve Sharpens’ sign where you need to drop to 15 mph before speeding up to avoid getting run over by the cars on the 17.

    … If you’ve ever driven it, you’ll remember it. If not, I’ll try to post the link later…

  5. Steven Peters

    December 19, 2010 - 2:32 pm

    None of my favorite crazy sharp turns have recommended speeds. They just have arrows pointing which way the turn is.

    I did find a link to a highway design guide that may be interesting to you if you want to see how many of these turns are designed. They apparently call the constant radius turns “horizontal curves.”

  6. Dan Meyer

    December 19, 2010 - 3:14 pm

    The curve Elaine refers to is this one right here. I drove past it hundreds of times when I lived in Santa Cruz and it blew my mind every single time. It’s my inspiration for this WCYDWT unit.

    @Everyone, thanks for helping out.

  7. Aaron F.

    December 22, 2010 - 8:28 pm

    Here’s one in suburban Michigan!,-83.308575&spn=0.00467,0.017166&z=17&layer=c&cbll=42.566493,-83.308449&panoid=9QbI6CxZglgQ0P987kT7Uw&cbp=12,130.69,,0,-11.82

    And here’s another!,-83.32497&panoid=KfllLYsdQTO_79btRDmGtg&cbp=12,90.89,,0,5&ll=42.568759,-83.325098&spn=0.009276,0.026157&z=16

    Strangely, there’s no sign for drivers going the opposite direction…

  8. barefootmeg

    December 29, 2010 - 4:34 pm

    wow! looks like you’ve got a lot already.

    this road near silverton is like that scene in pee wee herman’s big adventure where you get multiple curvy’s. there’s no specific addresses, but if you google for Silverton, U.S. 550, CO you’ll see what i mean in terms of curviness. many of those curves have signs before them.