(logo whooshing)
(gentle foreboding music)
- [Narrator] Crash tests were performed
on a new guardrail system that was designed
to solve a specific problem.
(truck crashes)
TxDOT wanted researchers to see
if a lightweight guardrail system could be developed
that would meet new testing standards.
- Ultimately, we were trying to prevent
or reduce cross-median crashes.
- Whenever you have two opposing lanes of traffic
that are close to one another,
it's always a good practice to have a barrier
installed between them.
That prevents traffic from one side,
somebody from one side to accidentally
come into the opposing lane of traffic
and result in a head-on crash,
and these are crossover crashes, and they're usually fatal.
- We have a concrete barrier
that does that, but we have some bridges
that can't support the weight of a concrete barrier
and this rail, this median rail will be lightweight
and prevent the cross-median crashes.
- [Nauman] We looked at the existing metal guardrail systems
and we kind of used as much of the design
as there is already and then adapted it for use
on top of the surface.
In our design, we had a rail system
that's also supported by posts,
but these posts are now just bolted onto the concrete.
A key design aspect for this system
was to look at how the post detaches
or deforms where it is attached
to the concrete.
It is important to have the right release
of that post or right defamation of that post,
if it deforms too quick, if the connection is too weak,
then your whole guardrail will be very weak
and it might not actually prevent the vehicle
from breaching and going to the opposing lanes.
And at the same time, if that connection is too stiff
or doesn't release quickly,
then you would have a very stiff system,
and that can lead to the vehicle kind of snagging
onto the barrier, resulting in a rollover,
or it may just cause rupture to the rail
or something like that.
- [Christopher] We tested to MASH Test Level 3.
So, we tested a small car and a pickup truck
on the median rail, both passed with flying colors,
it looked really good.
- [Nauman] We expect this design
to be more cost effective than concrete barriers,
and at the same time it's going to be much lighter
than a concrete barrier, so it can be used
on top of bridges and also on concrete pavements.
- [Narrator] For more information
and to find the publications for this project,
please visit the TxDOT research library
at the link shown below.