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(logo whooshing)

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- Rumble strips are an
inexpensive way to alert

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drivers who may inadvertently
leave their assigned roadway.

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But when these same roads
are repaired and newer layers

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of seal coat are added, they're
effectiveness can diminish.

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The Texas A and M Transportation Institute

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and the Texas Department of
Transportation are looking

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into how seal coat application can lead

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to a drop in the
performance of these strips.

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- So rumble strips are a very common,

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low cost, effective measure
for reducing crashes.

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The problem is that we do seal coats

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to maintain these roadways,

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especially rural roadways, all the time.

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And when you put a seal coat down,

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you're going from one edge of the pavement

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to the other, and you're gonna
cover up the rumble strips.

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So over time, you're gonna have

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less effective rumble strips, just 'cause

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you're doing pavement maintenance.

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- The project at first,
was really intended

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to answer a basic question.

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How many times can we seal coat

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over milled rumble strips
on the side of the road?

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Is it one time, is it twice,

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or is it dependent on the location?

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We need to find a way to make sure

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that we're preserving the
road and maintaining it, but

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at the same time that our
rumble strips are effective

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and they're providing
their intended effect.

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- We had 55 rumble strips
(gravel whooshing)

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identified that were

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gonna be seal coated.

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So we evaluated the noise
and vibration performance

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of these rumble strips

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before and after the
seal coats were applied.

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We found that if you know

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the rumble strip performance beforehand,

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you can predict what it's gonna be

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after the seal coat goes down.

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So we developed a design tool that TxDOT

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can go collect some
information in the field.

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What they need to do is go to the field,

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and measure the noise
performance beforehand.

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Using a sound level
meter, much like this one,

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they can measure the rumble
strip performance initially.

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Also, they can get rumble strip depth,

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the speed limit, and the
seal coat type, and put those

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into the model and predict
the rumble strip performance.

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- The biggest benefit that will come out

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of this, is a process that we can follow

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as an agency, simplified tool

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so that this decision is easy to make,

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and folks that are involved

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in doing the seal coats
aren't left to make a

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determination that otherwise
can be kind of complicated

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by going with a rule of
thumb that we may not

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be sure meets the
(rumble strip buzzing)

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intended effect of the rumble strips.

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We're really tying in
maintenance and preservation

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of roadways, along with
operations, which is typically more

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about safety and moving
traffic along the highway.

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We're really trying to draw
those two fields closer

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together to ensure that not only

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are the roads maintained as best as we can

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with as minimal amount
of money as possible,

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but at the same time,
we're meeting our goals

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of safety and and trying to
move towards mission zero,

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where in the future we don't
have any roadway fatalities.

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Now those two fields are
really merging together

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in a way that benefits
the traveling public.

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- For more information and
to find the publication

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for this project, please visit the TxDOT

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research library at the link shown below.