(logo whooshing)
- Rumble strips are an inexpensive way to alert
drivers who may inadvertently leave their assigned roadway.
But when these same roads are repaired and newer layers
of seal coat are added, they're effectiveness can diminish.
The Texas A and M Transportation Institute
and the Texas Department of Transportation are looking
into how seal coat application can lead
to a drop in the performance of these strips.
- So rumble strips are a very common,
low cost, effective measure for reducing crashes.
The problem is that we do seal coats
to maintain these roadways,
especially rural roadways, all the time.
And when you put a seal coat down,
you're going from one edge of the pavement
to the other, and you're gonna cover up the rumble strips.
So over time, you're gonna have
less effective rumble strips, just 'cause
you're doing pavement maintenance.
- The project at first, was really intended
to answer a basic question.
How many times can we seal coat
over milled rumble strips on the side of the road?
Is it one time, is it twice,
or is it dependent on the location?
We need to find a way to make sure
that we're preserving the road and maintaining it, but
at the same time that our rumble strips are effective
and they're providing their intended effect.
- We had 55 rumble strips (gravel whooshing)
identified that were
gonna be seal coated.
So we evaluated the noise and vibration performance
of these rumble strips
before and after the seal coats were applied.
We found that if you know
the rumble strip performance beforehand,
you can predict what it's gonna be
after the seal coat goes down.
So we developed a design tool that TxDOT
can go collect some information in the field.
What they need to do is go to the field,
and measure the noise performance beforehand.
Using a sound level meter, much like this one,
they can measure the rumble strip performance initially.
Also, they can get rumble strip depth,
the speed limit, and the seal coat type, and put those
into the model and predict the rumble strip performance.
- The biggest benefit that will come out
of this, is a process that we can follow
as an agency, simplified tool
so that this decision is easy to make,
and folks that are involved
in doing the seal coats aren't left to make a
determination that otherwise can be kind of complicated
by going with a rule of thumb that we may not
be sure meets the (rumble strip buzzing)
intended effect of the rumble strips.
We're really tying in maintenance and preservation
of roadways, along with operations, which is typically more
about safety and moving traffic along the highway.
We're really trying to draw those two fields closer
together to ensure that not only
are the roads maintained as best as we can
with as minimal amount of money as possible,
but at the same time, we're meeting our goals
of safety and and trying to move towards mission zero,
where in the future we don't have any roadway fatalities.
Now those two fields are really merging together
in a way that benefits the traveling public.
- For more information and to find the publication
for this project, please visit the TxDOT
research library at the link shown below.