To my knowledge, the adhesives used are dependent on the substrate (concrete,
asphalt, etc.) and the material(s)to be applied (rubber, vinyl, plastic,
fiberglass, etc.) Of course the adhesives will need to 'stand up' to the
environmental condtions, too: heat, cold, rain, snow, traffic loads, ambient
chemicals/pollutants, etc.

The Transportation Research Board recently published a Synthesis report on
experience of various installations:
www.trb.org/TRBNet/ProjectDisplay.asp?ProjectID=1521

Also, NCHRP project 4-33, currently underway, is developing specific selection
criteria from actual environmental chamber tests.

Mr. Gravel - The Nevada Department of Transportation does not allow the use of
adhered detectable warnings; we require products that are: [a] cast into the
concrete as part of the ramp or sidewalk or [b] inter-locking paving stones set
into compacted gravel and bedding sand. I am considering disallowing the
latter. The adhered detectable warnings that exist on our facilities are those
that are installed and maintained by local public agencies at their expense.

Thank You Dennis. What is the primary reason for not using surface applied DW
tiles?

Is there anyone else in the industry who may be able to help me better
understand how much (as a percentage) of retrofit DW tiles are actually adhered
(with or without anchor bolts).

Thank you to everyone for your help.
Shamsi

Let me start by letting you know we are a DWD manufacturer. We manufacture a
cement based cast in place product. Before getting into this business we
manufactured high end fiberglass hot rod (pre 1948) car bodies. With extensive
knowledge of fiberglass and resin based products we realized that any DWD
product made with resin would not hold up to UV or heavy traffic. There is NO
WAY to stabilize resin, you can only hope to prolong damage over a period of
time. Therefore any overlay product will not last as long as a cast in place
system.

I purchased a 1929 Model A fiberglass roadster body a year ago and have been
getting it ready to paint. I noticed the letters DWI or 1 on the firewall,
followed by 4 digits. I'd like to see when it was manufactured and if there
may be any paperwork of any kind available, such as a title or application for
a title, for when it's ready to drive. Any help would be greatly appreciated.
I'd also love knowing the history of the car and perhaps when it was
manufactured.

Thanks!

Paul Cunningham
Willis, Texas
(3936)520-8550

I might be able to shed some light on why adhesive-based DWD's are not approved
for use on the State highway system in Arizona. Our research and field trials
showed that the glue line between the DWD and the sidewalk could not handle the
thermal stress of daily 40 degree fluctuations in temperature and yearly 100
degree fluctuations. The glue lines failed and the tiles peeled up, creating a
tripping hazard. Until summer 2007 I was the standards engineer for the
department and wrote the criteria for DWD's, developed the standard drawings
for their installation, and evaluated all the products for inclusion on the
State Approved-Products List. Hope this helps.

Mr. Gravel: The primary reason we do not use adhered DWs is due to the
relatively short service life of these systems. Since Nevada is a
geographically large State with a small population, most of our road-miles are
rural in nature; we therefore do not have a lot of locations on our system that
require detectable warnings as opposed to more urbanized jurisdictions. It is
perhaps for this reason that we can use only highly durable, long lasting
systems and get an acceptable benefit to cost ratio. We do not want to burden
our already taxed maintenance forces with the additional requirement of
inspecting and repairing detectable warnings. Furthermore, the safety problems
that arise from failed systems is a related and important consideration; they
must be corrected in a timely manner or the State may be held liable for any
unfortuante consequences. It is our position that casting-in-place is the most
reliable and durable method of installing detectable warnings and yields the
best return on investment for our situation.

Dennis Coyle said in his post that the Nevada DOT prefers a cast in place
system. What kind of cast in place system(s) do you use?

I agree that most surface applied systems fail. Rigid plastic panels and
adhesive with fasteners is a poorly designed system. Safetysteptd is a flexible
system that bonds polymer concrete mats to the surface without mechanical
fasteners.
Key features...flexible,bonds to concrete or asphalt and can be fabricated to
the proper size on site.

You can view our list of qualified detectable warnings at the following web
page: www.nevadadot.com/reports_pubs/qpl/pdfs/QPL.pdf You may notice that we
have not approved a plastic product. This is not from a lack of cast-in-place
models, its because they have not met our requirement for proof of acceptable
service life. The one exception is ArmorTile; while they have met our
durability requirement they have not provided the test results for certain
standard ASTM material property tests for plastics that we require. If you
want a copy of our position paper on detectable warnings you can email me at
dcoyle@dot.state.nv.us and I will send it to you.

First, let me disclose that I am a manufacturer of detectable warning tactile
mats and also of traffic safety devices. My company's experience is that
polyurethane adhesives will securely bond DW panels in place on a variety of
substrates. Two primary characteristics will help your selection, elasticity
and temperature range. The adhesives we use have a 400% to 600% elongation at
break, so if there is expansion or contraction in the substrate or panel, the
adhesive will also move. Next, these adhesives have service temperature limits
of between -40 degrees F up to or beyond 170 degrees F, so they are suitable
for all locations. Just sourcing a "urethane" adhesive is not enough, you must
check the property data to get the proper performance characteristics. Lastly,
a common source of failure for surface applied tactile mats is improper
installation due to poor surface preparation. If the substrate is oily or
crusted with mineral deposits or covered with dirt, no adhesive can do it's job
to hold that mat down. I hope this helps. Frank J. Dvoracek

I have watched the progress of these Mats glued down to the substrate for two
years now, so far after the first 6 months the sides cam up pulling the anchor
bolts off. After a year the sides of the mats became brittle and started to
break off due to they were curling up and people were tripping over them.
Secondly these Mats are placed down at places where the Blind do not walk, they
are placed in front of the Home depot all along one side of the building where
only the seeing go and many shopping carts, I have heard the response from the
people, why are they here, they are annoying.
This year alot of them are missing, the contractor always comes back and
replaces them, I just wonder now that these Mats are being tested by the
Manufacturer on the job site and more is being added I just don't understand
the reasoning behind it all when the product fails after one year or even two
then they come off. So this means after 5 years guess who pays for it then.
I just don't understand the reasoning when all the blind are asking is for
something that works for them thats detectible under foot. a way finding
solution isn't this what the Mats are intended for?

Hi Ron, The mats infront of Home Depot are probably from the affiliated company
White Cap (which is a distributor of a Detectable Warning product). The use of
a surface applied ruberized mats require the adhesive to work properly under
ideal conditions (no traffic and not in direct sunlight). The problem is the
glue/adhesives used. Most installations do not cover the entire undersurface
where the mat makes contact with the subsurface. The mats infront of the two
Home Depots I go to also have to be replaced almost every 4 to 8 months just
with typical wear. I have seen a product that has handled over 7 million
pedestrians in 5 years with no loss of domes (only a discoloration from the
sun. It was yellow on concrete.) There have also been fully loaded cement
trucks driving over it. It also handles dry wheel steering, is low profile,
surface applied retrofit, and about about $12 per square foot in materials. No
anchor bolts or drilling. I did some research on a test installation. I found
out the inventor of it showed some Detectable Warning Salesmen his product and
weeks later they were chipping at the domes trying to figure out how the test
product was holding up so long. I heard the product is still looking for a
manufacturer.
Plastic or plastic composite Detectable Warning mats tend to warp and become
brittle in the sun. The Detectable Warning surfaces are required where there
is a hazardous transition and is usually on a flat surface where the visually
impared can't see or feel where the safty ends. The Detectable Warning
concrete inserts require the existing concrete to be pulled up and replaced
resulting in a costly and timely process. The hidden costs are the concrete
materials and labor to replace or add Detectable Warnings at an intersection...
or to replace any defective ones. The concrete pavers or tiles to be inserted
are the cheapest part of the project. Most Detectable Warning Salesmen don't
like to talk about the hidden costs accociated with their products (i.e.
replacement costs and how often, demo and rebuild costs, dry wheel steering for
those using part of the Dectectable Warnings to turn their vehicle around,
tripping hazards for those plastic type mats curling or warping.) If the
Detectable Warnings do not work or installed properly can also add lawsuit
costs (something most manufactures will not warant).
Just a few extra things to be considering in your Detectable Warning search...
good luck!

Hello and Thank You for the reply,
most people know who I am and what I do, I will not advocate my self here. I
travel to most parts of the world, I recently came back from the Island of
Bali, they used a cement adheared dome type of DW and guide way strips of 2
inches wide and 1/8th inch in highth. I felt them walking on it and it felt
like a Bubble and not detectible under foot. I agreed with the Indonesian gov
that a system needs to be standerdized through out the world and not differ
from country to country or for us State to State. I speak to blind
organizations in most parts of the world, all blind people have one thing in
common is that they are blind and cannot see although their sences are sharp.
They use the curb or a wall for a cane que. If anything was placed on the
ground for detection they would use that also. I also just came back from
another country where the temp was higher then 160 on the cement substrate.
Most adheasives if not all will fail after the heat is up to past 120.
It's just very disturbing, when the Blind do not actually walk alone anywhere
in the States, they are forced to stay home due to there own safety. although
if we would just place DW's and a way finding solution at Bus stops, railway
platforms, taxi ranks, airports,and shopping malls entrances then the blind can
at least have the freedom to walk and travel as the seeing do. Places like the
Home Depot makes no sence and is only a money maker for the manufacurer. I have
only seen these mats fail regardless of who say's what about a mat that has
been down for so long and everybody is trying to distroy it. In Europe they
have a great solution and this very product is being used in 18 different
countries right now after being tested for 20 years, no matter what kind of
heat or ? but this system needs to be taught to the blind and is a very good
success there as a international language for the Blind.