On the sides of most highways (in the U.S. at least), there are rough treads just outside the travel lanes to snap a driver to attention if the vehicle is drifting off the road. Is there a name for these things?

EDIT (post-answer for clarification, needed the answer to find the picture)
From the U.S. Department of Transportation's webpage:

rumble strips

  • I call them wake-up bumps. As you drive over them, they make a heartbeat sort of sound, or as I hear it, 'wake up, wake up'. Commented May 4, 2012 at 1:39
  • I've always grown up calling them "Growlers" its always sounded like the car growls.
    – user88828
    Commented Aug 20, 2014 at 18:34
  • It should be noted that there are several different variations. The pictured strip is created by grinding away the pavement, with depressions about a foot apart and maybe an inch or two deep. There are others that consist of raised asphalt bumps, usually farther apart, and I've heard of schemes using paint or perhaps glue-on plastic grids which produce a "tone" when driven on. I've mostly seen the above scheme in the US Midwest, and it is generally called a "rumble strip".
    – Hot Licks
    Commented Dec 25, 2014 at 3:33

4 Answers 4


Those are called rumble strips.

  • Wow. How simple. Now I realize I have definitely seen/heard the phrase before.
    – yoozer8
    Commented Oct 3, 2011 at 18:47
  • Also (at least in some regions) "Wakeup strips" or "Wakeup bumps".
    – user597
    Commented Oct 3, 2011 at 22:38
  • Yeah, when they first started to appear maybe 1980 they were called several things (which I forget), but they are by now pretty much universally "rumble strips" in at least the US Midwest.
    – Hot Licks
    Commented Dec 25, 2014 at 3:29

There's another variant here in Australia (and NZ, and I'm sure in other places too), which is a set of raised paint lines on the road which will give you a rumbling sound as you drive over them. The same technique is used in transition areas from high to low speed (like a highway exit) or where two lanes of high-speed traffic will be merging, that kinda thing where you want people to be awake.

A sample can be seen here, clearly showing the raised paint goop.

They're called, logically enough, 'audible lines', and are best defined as:

...a line on a road that is made up of a series of closely spaced raised pieces of material designed to create a continuous noise or vibration if driven on by a motor vehicle

(Reg 323A, New South Wales Road Rules 2008)

  • And yes, I'm off to edit Wikipedia to insert that reference too in a moment :)
    – tanantish
    Commented Apr 26, 2012 at 22:41

In Pennsylvania they are called SNAPs by PennDot, which stands for sonic nap alert patterns.


They are called SNAPs: Sonic Noise Alert Pattern.

  • 3
    What's your source for this answer? In some quick googling, I found this acronym expanded as Sonic Nap Alert Pattern, so it seems there is some confusion.
    – Marthaª
    Commented Apr 26, 2012 at 22:23
  • 2
    "Sonic noise" does seem a bit redundant.
    – Hot Licks
    Commented Dec 25, 2014 at 3:34

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