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(gentle music)

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- [Narrator] With freight
traffic on the rise

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TxDOT wanted to ensure that motorists

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are as safe as possible
especially in corridors

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where freight and truck
traffic is the highest.

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Meeting Test Level 4 standards
with metal guardrail systems

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has never been attempted until now.

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- You'll commonly see our
guardrails on the side of highways

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and those guardrails are are
meant to protect motorists

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from getting off the road.

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- A high percentage of, you know,

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serious accidents and
fatalities are associated

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with the driver leaving the roadway,

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not necessarily an impact
with another vehicle.

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So yes, they do save a lot
of lives on a yearly basis

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and TxDOT literally has thousands of miles

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of metal beam guard fence in the state.

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Texas has a lot of heavy
trucks as well as we have

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a pretty substantial Texas
highway freight network.

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Typically most guardrail is tested

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to what's called Test Level 3

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which basically means 62 miles per hour

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for a 5,000 pound pickup.

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But Test Level 4 takes it up a notch

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and basically this is a 22,000
pound delivery type truck

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that is tested at 56 miles per hour.

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Obviously that's gonna have
a lot more kinetic energy.

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And so the intent is to have
a more durable guardrail

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for those high truck traffic
and freight network areas.

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- Texas already has a
lot of concrete barriers

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that provide the same level of containment

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for freight trucks, but
this is a metal guardrail

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and there are several benefits
to having a metal guardrail.

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It's expected to be cheaper
than a concrete barrier,

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it's more open design on highways.

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We will also be able to
transition much easier

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from this guardrail to
a standard guardrail

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which is not Test Level 4 guardrail

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which is why Texas wanted
to have this design

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as one of their standards.

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- [Kenneth Mora] There
were various alternatives

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that were looked at and
the final alternative

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that was selected basically
is about 40 inches tall,

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so it's a little taller
than the standard guardrail

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and at the top, it has
a box beam type element

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to assist in the absorption of energy.

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- [Nauman Sheik] We were trying
to use as many components

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of existing hardware that Texas uses.

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There's a benefit to doing that.

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They're able to use the same hardware,

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they don't have to inventory
a lot of different hardware.

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We did very detailed computer simulations

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where we were impacting
these guardrail design

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with different vehicles, as we
would do later on in testing.

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Once we were satisfied with the design

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that it's working the way we want it to

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then moved on to a
full-scale crash testing.

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On this guardrail we performed
three different tests.

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The first test was with a freight truck.

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It's basically a single unit truck.

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It weighs about 22,000 pounds.

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We also tested with the
small car and the pickup

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which were also contained and
redirected by this barrier.

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- [Kenneth Mora] We'll start developing

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a roadway design standard
for this particular unit

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and provide guidance on it's application,

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what recommended application
areas in the standard.

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There will be a new standard related

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to the TL... for a metal
beam guard fence system.

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- [Narrator] For more information

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and to find the publications
for this project,

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please visit the TxDOT Research Library

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at the link shown below.