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Recessed Reflectors- Are They Worth It?

Started by paulthemapguy, January 04, 2023, 12:24:56 PM

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paulthemapguy

I got wind that my county is looking to use more recessed RRPM's (reflectors) in asphalt paving projects.  I wanted to ask if other people out there had success stories or complaints about them.  Do they hold up better against snowplow blades in the winter? Are there varying recess depths, where one is superior to the other? These would have course be the reflectors placed in the northern states, so they're put in a "shoe" and adhered to the inside of a cutout hole with epoxy. By "recessed", I mean a long, rectangular groove would be cut, with the long side of the rectangle along the longitudinal direction so people can see into the groove from the upstream and downstream directions.
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Big John

Wisconsin used to have them but found them ineffective, thus removing many of them. Retroreflective lane lines work better.

hbelkins

Yes, they are a blessing on rainy nights. It doesn't matter what kind of lane line markings are used, they're hard to see when the pavement is wet and especially if you meet oncoming traffic.

Oddly enough, Kentucky is moving away from using them on two-lane roads, which seems counterproductive to me. I think they're better when used to delineate lanes of opposing traffic, especially on narrower rural roads, than they are multilane roads.


Government would be tolerable if not for politicians and bureaucrats.

J N Winkler

Caltrans uses them extensively (at least in northern California) and they work well.  On the other hand, the Kansas Turnpike tried them about 20 years ago and discontinued them.  So there is clearly a spread of opinion as to whether the gain in nighttime delineation outweighs the disadvantages, which I suspect include both maintenance liability and enhanced debris hazard if the shoes come loose.
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

Rothman

I believe NYSDOT has found recessed reflectors to have too high of a maintenance cost and the original premise that plows would not damage them didn't really come to fruition.  This has also led NYSDOT to opt for epoxy lane markings as the alternative.

I like reflectors and think lane visibility improves with them over the silhouetted markings in the dark rain, though.

(personal opinion emphasized)
Please note: All comments here represent my own personal opinion and do not reflect the official position(s) of NYSDOT.

J N Winkler

I guess my question would be how recessed reflectors compare with patterned cold plastic markings (which are secured to the road surface with adhesive and are designed to have enhanced visibility in rain) as a spot treatment for curves.
"It is necessary to spend a hundred lire now to save a thousand lire later."--Piero Puricelli, explaining the need for a first-class road system to Benito Mussolini

ErmineNotyours

My stepdad said that the holes for recessed reflectors tend to collect water, freeze and cause potholes.  This is according to his observation of Oregon installations.

JoePCool14

Recessed reflectors are fantastic when it's wet. Just last night, I was driving in the wet, and the reflectors were the only thing I could clearly see when it came to lane markings. Most of the roads I was on could've also used a re-striping.

Given the costs vs. benefits, I think they are very useful for at least delineating the centerline, especially around corners. Drivers around here tend to drive too close to the centerline and part of that is because the centerline is simply hard to see.

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jeffandnicole

The reflectors make seeing the lanes in rainy weather so much easier, as others have mentioned.

Regarding plows: it's not so much the plow that's the issue, but rather the wheel or "skid" that helps balance the plow on the road.  If this is too narrow, the skid or wheel has a tendency to hit the reflector, breaking them. 

As far as potholes go, I haven't seen that happen too often, since the divit needed for the reflector isn't that deep. If the seam or expansion joint used between paving lanes runs thru the area where the reflector is, it will create problems though.

paulthemapguy

To be clear, I'm not asking if reflectors are worth it. I'm asking if it's worth it to use recessed reflectors rather than ones placed at the surface. To recess the reflectors downward into the pavement involves cutting a long, narrow groove that is a couple inches deep, and placing the reflector at the base of that groove.  The purpose of this is to reduce damage incurred to the reflectors by snowplow blades in the winter.
Avatar is the last interesting highway I clinched.
My website! http://www.paulacrossamerica.com Now featuring all of Ohio!
My USA Shield Gallery https://flic.kr/s/aHsmHwJRZk
TM Clinches https://bit.ly/2UwRs4O

National collection status: 361/425. Only 64 route markers remain

hbelkins

Quote from: paulthemapguy on January 17, 2023, 12:48:02 PM
To be clear, I'm not asking if reflectors are worth it. I'm asking if it's worth it to use recessed reflectors rather than ones placed at the surface. To recess the reflectors downward into the pavement involves cutting a long, narrow groove that is a couple inches deep, and placing the reflector at the base of that groove.  The purpose of this is to reduce damage incurred to the reflectors by snowplow blades in the winter.

Kentucky switched from the original design to the recessed markers several years ago in its new installations. Prior to that, it wasn't all that uncommon to see the old-style markers along the shoulders of the road after a snowfall. The recessed markers are much less prone to being dislodged by snowplows.


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jeffandnicole

Quote from: paulthemapguy on January 17, 2023, 12:48:02 PM
To be clear, I'm not asking if reflectors are worth it. I'm asking if it's worth it to use recessed reflectors rather than ones placed at the surface. To recess the reflectors downward into the pavement involves cutting a long, narrow groove that is a couple inches deep, and placing the reflector at the base of that groove.  The purpose of this is to reduce damage incurred to the reflectors by snowplow blades in the winter.

In an area where snow is expected, yes. Raised reflectors wouldn't last one snowfall.

Rothman

Quote from: jeffandnicole on January 17, 2023, 01:08:15 PM
Quote from: paulthemapguy on January 17, 2023, 12:48:02 PM
To be clear, I'm not asking if reflectors are worth it. I'm asking if it's worth it to use recessed reflectors rather than ones placed at the surface. To recess the reflectors downward into the pavement involves cutting a long, narrow groove that is a couple inches deep, and placing the reflector at the base of that groove.  The purpose of this is to reduce damage incurred to the reflectors by snowplow blades in the winter.

In an area where snow is expected, yes. Raised reflectors wouldn't last one snowfall.
I believe MA found this out the hard way years ago.  I think I-91 had raised reflectors on it...for a brief period. :D
Please note: All comments here represent my own personal opinion and do not reflect the official position(s) of NYSDOT.

Dirt Roads

Back about 2006-07, NCDOT tested the use of recessed reflectors on backroads that had been recently repaved with tar-and-chip.  Those reflectors certainly improved nighttime visibility.  Of course, there were a bunch of these guys popped loose after the first big snow a few years later.  Those roads have now been repaved with tar-and-chip twice since then, and there was no attempt to "save" any of the reflectors.  The ones that remain are buried slightly below the top surface of pavement, and will reappear as the chippies wear down when we get close to needed another paving project.

JoePCool14

Quote from: paulthemapguy on January 17, 2023, 12:48:02 PM
To be clear, I'm not asking if reflectors are worth it. I'm asking if it's worth it to use recessed reflectors rather than ones placed at the surface. To recess the reflectors downward into the pavement involves cutting a long, narrow groove that is a couple inches deep, and placing the reflector at the base of that groove.  The purpose of this is to reduce damage incurred to the reflectors by snowplow blades in the winter.

Okay. Then the answer is yes to that question.

This is actually something that I give credit to IDOT for. All their roads get reflectors. And they hold up decently well too, for the most part.

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Revive 755

Quote from: JoePCool14 on January 17, 2023, 09:21:36 PM
This is actually something that I give credit to IDOT for. All their roads get reflectors. And they hold up decently well too, for the most part.

The IDOT reflectors are the raised variety (exceptions welcome).  Lake County, DuPage County, and occasionally Kane County used the recessed version. IIRC Cook County recently switched from raised to recessed reflectors.

JoePCool14

Quote from: Revive 755 on January 17, 2023, 10:30:45 PM
Quote from: JoePCool14 on January 17, 2023, 09:21:36 PM
This is actually something that I give credit to IDOT for. All their roads get reflectors. And they hold up decently well too, for the most part.

The IDOT reflectors are the raised variety (exceptions welcome).  Lake County, DuPage County, and occasionally Kane County used the recessed version. IIRC Cook County recently switched from raised to recessed reflectors.

Yes and no. IDOT doesn't grind off a long section of asphalt before and after the reflector. I'm not sure exactly how they do it, maybe I should read the construction specs that I have sitting next to my desk, but it is recessed in its own little case. I can see a pair of them outside my window and they definitely aren't above the pavement.

Road Guy Rob actually pointed this out in one of his older videos talking about Botts dots in California. He mentioned specifically what IDOT does at the very end of the video.

https://youtube.com/watch?v=1-A6hHG7-vc&si=EnSIkaIECMiOmarE&t=344

Keep in mind, this is referring to IDOT D1, so not all districts may do it this way.

:) Needs more... :sombrero: Not quite... :bigass: Perfect.
JDOT: We make the world a better place to drive.
Travel Mapping | 60+ Clinches | 260+ Traveled | 8000+ Miles Logged

Dirt Roads

Quote from: ErmineNotyours on January 17, 2023, 05:31:18 AM
My stepdad said that the holes for recessed reflectors tend to collect water, freeze and cause potholes.  This is according to his observation of Oregon installations.

The pilot project in my front yard actually took the time to spray a fresh layer of tar into the recesses before gluing down the reflectors.

Revive 755

Quote from: JoePCool14 on January 18, 2023, 09:15:01 AM
Keep in mind, this is referring to IDOT D1, so not all districts may do it this way.

It's in the IDOT Standard Specs, see Page 662 (679 of 1217) https://idot.illinois.gov/Assets/uploads/files/Doing-Business/Manuals-Guides-&-Handbooks/Highways/Construction/Standard-Specifications/2022%20Standard%20Specifications%20for%20Road%20and%20Bridge%20Construction.pdf

Quote from: IDOT Standard SpecificationsThe pavement shall be cut to match the bottom contour of the marker using a concrete saw fitted with 18 and 20 in. (450 and 500 mm) diameter blades. Diamond blades shall be used on portland cement concrete pavement.

Quote from: IDOT Standard SpecificationsThe installed height for the reflective pavement markers shall be approximately 0.3 in. (7.5 mm) above the road surface.



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