Here’s the thing. I don’t drive myself anymore. I have Ivy.
She’s a painfully slow driver. Which is good. Fast driving makes me nervous and white knuckled these days.
Some early mornings going to dialysis I can be bored to sleep. Other mornings I wanna scream and jump out of the car. I try and determine if I’d live at this slow speed.
But I have noticed the the idiot strip. You know the bumpy thing that tells drivers they are too close to the line.
How do they make that? I just wondered.
The technical term is Rumble strip - Wikipedia. Very broadly speaking, there’s two kinds.
In one kind they use something like an overgrown woodworking router to dig out a channel 2-3" wide and 3/4-1" deep crosswise versus the direction of travel and about 1 tire-width long. These are dug in one after the other just a couple inches apart. The net result is that strip of road surface is corrugated and vibrates your tires and steering if you drive over it.
The other kind involves gluing raised dots or bumpy plastic strips to the top of the roadway. Same outcome though: now you’re driving over something corrugated which shakes the car enough get drivers to pay attention. Maybe. Usually.
The dug-in kind are more compatible with snow plowing which tends to peel up the raised glue-ons.
I’m so happy you’ve told me. Now I can fall asleep happily.
And also, I was gonna ask about those reflective bump things. I have a bucket of them I picked up on the side of the road a long time ago. I wondered how and why they were removed.
How about virtual rumble strips?
Many cars detect lane departures, and can respond by vibrating the seat or the steering wheel.
These were some of the first: Botts’ dots - Wikipedia. Later versions got taller, sorta rectangular and had colored reflectors in them.
Invented in California to deal with foggy conditions. They’re not snowplow compatible, but a LOT of California is snow-free. I remember learning about them as a kid out there.
You blow my mind 
.
No, I knew about those virtual ones.
Not real sure I care. I just wanted to know about a road thing
You ever notice how they make a buzzing sound when you drive over them?
Well, someone did:
Lotta those around: Musical Road - Wikipedia.
Oh my.
My curiosity may have stumbled upon a new hobby.
Sheesh, I’m already wondering about tire differences…
I do tend to get lost in the vines about this kinda thing…
I’ve seen those on mountainous
roads, where each reflector is
recessed into a little depression
set into the road. So I think the
idea is so a snowplow goes over
the top of each reflector.
Here is a link (if this works right)
to the best picture of one that I
could find:
Here’s another wiki about the non-round ones: Raised pavement marker - Wikipedia. It covers a lot of the same territory.
Cross-posting my contribution to the “interesting random fact thread”:
A nearby stretch of road was nicely repaved, restriped, and new dots glued on. The blue dots were very obvious, being new and bright and shiny, and I realized I didn’t know their purpose. I remembered to Google them up this morning: they are there to denote fire hydrants right opposite them at the curb. The blueness makes it easier for firefighters to quickly find a hydrant even if it’s foggy, smoky, trafficky, or chaotic. So now I know.
Speaking of hydrants, I know of several in Livermore, CA, that are purple. I was under the impression they were required to be red or yellow, and very bright shades, at that.
Lotta things are more local than folks realize.
Around here we have the raised reflectors in the middle of the lane to mark hydrants. But the dots are yellow.
Hydrants around here tend to be white.
I like how LSL_Guy mentioned the Raised Pavement Markers. I don’t think they adhere too well to asphalt here in San Diego. They still have a thick layer of crud on the bottom of each one after they get torn off by vehicles. It would probably take too much work for the road crews to reuse them.
The first version of the concept was from the UK in 1934, known as cats eyes
Those cats’ eyes do look great. Since they’re cast-iron, they must be more hardy than my yellow plastic ones.
When I was growing up in Texas I knew a kid whose Eagle Scouts project was to put blue(?) reflectors at all of the fire hydrants. I don’t recall if he actually installed them, raised money to install them, or just lobbied the city to do it. Residential streets generally didn’t have any reflectors or painted lines, so the raised blue reflector really stood out.
Another type of rumble zone you will only encounter on major highways is to warn drivers they are approaching something, like as you get to the braking zone on a freeway exit. Here in Cleveland there is an extensive zone as you approach Dead Man’s Curve where I-90 makes a sharp turn to the east at the lake shore. And the rumble strips are always grouped in odd numbers with a longer rest in between.
Brrrp, brrrp, brrrp - .brrrp- .brrrp, brrrp, brrrp, brrrp, brrrp…
Ah yes, driving by Braille.
I once got a loaner car that had that lane sensing thing. Sooo annoying, in addition to vibrating, it tried to steer back into the lane. Look, stupid car, I’m trying to change lanes.