Slate.com: Reflections on Things That Go Bump in the Night (http://www.slate.com/blogs/the_eye/2014/01/23/what_s_that_thing_a_brief_history_of_reflective_pavement_markers.html)
QuoteDriving along a stretch of American asphalt in the dark of winter, you may notice that the road doesn't seem to get quite as dark as it used to. One reason? Those little reflective bumps along the pavement. Some of these reflectors come in unsurprising colors–red, yellow, white. What about the blue ones, though? And the green ones? Are they purely an aesthetic choice, or is there a reason behind the color variations?
QuoteBrent Johnson, general manager of the well-named Centerline Supply Ltd., in Grand Prairie, Texas, told me that these reflectors are called pavement markers, raised pavement markers, reflective pavement markers, or RPMs.* And it turns out the colors do have meaning.
QuoteRed, as usual, is bad. It typically indicates you're going the wrong way. If you turn around–probably a good idea–the RPMs will likely appear white or yellow to those driving in the correct direction. Yellow (or amber) markers typically show the center line of a road, or the left edge of a one-way road. White markers separate lanes of same-direction traffic and may also appear on the right edge of the road.
The only "bumps" around here in the night are the frost heaves you just ran over. These pavement markers need to be embedded in the pavement or they'll be plow victims after the fist snow.
I have never seen them.
Quote from: 1 on January 24, 2014, 07:26:40 PM
I have never seen them.
Nor have I. They must not have them in the US.
We've had them for 70 years, and call them cats eyes, because that was the inspiration.
Quote from: Brandon on January 24, 2014, 06:52:01 PM
The only "bumps" around here in the night are the frost heaves you just ran over. These pavement markers need to be embedded in the pavement or they'll be plow victims after the fist snow.
I agree.
At least some states specify
plowable pavement markers for exactly that reason.
They look like "regular" markers, but are recessed in pavement, and most of them escape damage by passing plows.
For blue markers, it is for the fire department as it tells then a hydrant is on the sude of the road there.
Quote from: NE2 on January 24, 2014, 07:36:07 PM
Quote from: 1 on January 24, 2014, 07:26:40 PM
I have never seen them.
Nor have I. They must not have them in the US.
"Driving along a stretch of
American asphalt..."
They're pretty ubiquitous in Washington.
I'm being snarky. I assume 1 is confused.
Quote from: NE2 on January 25, 2014, 04:11:39 PM
I'm being snarky. I assume 1 is confused.
Some places do, some don't. Wisconsin, for example, does not have reflectors that I have seen, embedded or raised. It may be that Massachusetts and New Hampshire don't have them either. He's only 15 after all, not older than the 900 year old man.
Quote from: NE2 on January 25, 2014, 04:11:39 PM
I'm being snarky. I assume 1 is confused.
Fair enough. Somehow I missed your typical snark in that post.
Quote from: Brandon on January 25, 2014, 11:25:23 PM
Quote from: NE2 on January 25, 2014, 04:11:39 PM
I'm being snarky. I assume 1 is confused.
Some places do, some don't. Wisconsin, for example, does not have reflectors that I have seen, embedded or raised. It may be that Massachusetts and New Hampshire don't have them either. He's only 15 after all, not older than the 900 year old man.
WI uses plowable reflectors, but not on all freeways yet.
Kansas experimented with raised reflectors (not sure whether they were of the snowplowable type) about ten years ago on the Turnpike, but has since removed them and has not (to the best of my knowledge) installed them anywhere else. Kansas now generally relies on thermoplastic for pavement delineation, with patterned cold plastic at spot locations (such as ramp diverges where the ramp design speed is significantly lower than the mainline design speed) where the enhanced reflectivity is considered to justify the much higher lifecycle cost.
In jurisdictions that do use raised reflectors, I suspect that rain and fog have a much heavier influence on the cost-benefit calculation than they would in Kansas and other states with arid or semi-arid climates.
Quote from: Big John on January 26, 2014, 08:58:07 AM
Quote from: Brandon on January 25, 2014, 11:25:23 PM
Quote from: NE2 on January 25, 2014, 04:11:39 PM
I'm being snarky. I assume 1 is confused.
Some places do, some don't. Wisconsin, for example, does not have reflectors that I have seen, embedded or raised. It may be that Massachusetts and New Hampshire don't have them either. He's only 15 after all, not older than the 900 year old man.
WI uses plowable reflectors, but not on all freeways yet.
Plowable markers
used to be standard in Wisconsin (seen most often first in the SE Region), but only on freeways and expressways. I've never seen any, but you might
rarely find a handful on a state highway. I don't know of any Wisconsin city to have ever used them. WisDOT has removed them from the standard specs in favor of grooved in wet reflective tape, either as an add-on in similar size to the older embedded reflectors or as the complete lane line skip-dash (the former being used on newer, longer stretches of roadway).
You're lucky to see the lines on the roads in my state at night, whatever reflective paint they use is not that reflective. The only place I've seen reflectors used are on the interstates. The reflectors are the embedded ones in the pavement that supposed to be "plowable", but they only last a couple of winters at most
Quote from: J N Winkler on January 26, 2014, 10:00:54 AM
In jurisdictions that do use raised reflectors, I suspect that rain and fog have a much heavier influence on the cost-benefit calculation than they would in Kansas and other states with arid or semi-arid climates.
Raised pavement markers are widely used in southern Nevada, particularly in the Las Vegas Valley. They are used instead of lane lines on all major freeways and most major arterials.
I recall reading somewhere (some time ago, so not certain on details) that the lack of rain was one reason for their use. The grime on the roads would rarely get washed away so lane lines needed painting more often, but RPMs tended to stay in place for much longer periods.
It's also the safety aspect as well, keeping people in lanes with the tactile and audible response of driving over the bumps as a lane drift alert (without the really loud affect rumble strips have).