Summer Institute 2012: Roadside Safety in the Classroom
1. Roadside Safety in the
Classroom
David Gutierrez, B.S.C.E., E.I.T.
Graduate Research Assistant
Midwest Roadside Safety Facility
University of Nebraska-Lincoln
June 13, 2012
2. Midwest Roadside Safety Facility
History
1974 – Started at UNL by Dr. Edward R.
Post
1990 – Officially named Midwest Roadside
Safety Facility (MwRSF)
Formation of the Midwest State’s Regional
Pooled Fund Program
1992 – New Director, Dr. Dean Sicking
3. Midwest Roadside Safety Facility
Midwest Roadside Safety Facility
Internationally-known research facility
Expertise in roadside and motorsports safety
Part of Nebraska Transportation Center - UNL
MwRSF staff
3 faculty (2 academic & 1 research)
4 engineers & 2 post-doctorial
4 research/technical staff & 1 office manager
9 graduate & 14 undergraduate students
4. Midwest Roadside Safety Facility
Sponsors
• State DOTs
• FHWA
• Private industry
• Motorsports
organizations
5. Midwest Roadside Safety Facility
Why is Roadside Safety Important?
Approximately
40,000 vehicle
accident fatalities per
year
30% of these involve
run off road
accidents
Estimated cost have
reached well over
$50 billion annually
6. Midwest Roadside Safety Facility
Roadside Safety is Working
For the past 40 years the number of
fatalities per year has remained nearly the
same
Vehicle traffic has increased 2.5 times
Fatalities per vehicle mile has decreased by ½
Due to increases in roadside safety and
vehicle safety as well as roadway
geometrics
7. Midwest Roadside Safety Facility
Roadside Safety Devices
Types of Devices
End terminals and crash cushions
Flexible barriers (i.e. cable systems)
Semi-rigid barriers (i.e. guardrail systems)
Rigid barriers (i.e. concrete bridge rails)
Race track safety
Portable and permanent signs
Poles
8. Midwest Roadside Safety Facility
Evaluation Criteria
Structural adequacy
Vehicle must be brought to a controlled stop or
redirected back toward roadway
Vehicle trajectory
Cannot touch ground behind barrier
Vehicle must remain upright (no rollover)
Occupant safety requirements
Occupant deceleration limits
Occupant compartment integrity
9. Midwest Roadside Safety Facility
Cable Median Barrier
Purpose: Develop a cable
median barrier to be used
in a 4:1 V-ditch to prevent
vehicles from crossing
over into oncoming traffic
MASH testing required in
several locations
10. Midwest Roadside Safety Facility
Research Continues
7 tests
3 with original bracket
4 with keyway bolt
Research on keyway bolt continues
Research shifted to 6:1 V-ditch
11. Midwest Roadside Safety Facility
Standard W-Beam Guardrail
Designed in early 1960’s
for large sedans
Top mounting height – 27
5/8 in.
6-ft 3-in. post spacing
8 in. blockouts
Worked for over a quarter
century
12. Midwest Roadside Safety Facility
W-Beam Guardrail Weaknesses
Vehicles with high
centers of gravity
Installation height
sensitivity
Rail ruptures
13. Midwest Roadside Safety Facility
Midwest Guardrail System (MGS) Design
Top rail height raised over 3 in. (from 27
5/8 in. to 31 in.)
Blockout depth increased (from 8 in. to 12
in.)
Rail splices moved to midspans
14. Midwest Roadside Safety Facility
MGS Applications
On flat ground
Behind a curb
Over a low-fill culvert
With 5:1 flare
Attached to approach guardrail transition
On a slope
Without blockouts
On a MSE wall
With wood posts
15. Midwest Roadside Safety Facility
Computer Simulations
Used for analysis
and prediction of
complex physical
events
Reduction of tests
Prototype simulation
Finite Element
Analysis with LS-
DYNA
16. Midwest Roadside Safety Facility
Motorsports Needs
High-speed oval track
racing
Vehicle containment
provided by concrete
walls
Serious driver injuries
and fatalities an issue
Need for improved
safety
17. Midwest Roadside Safety Facility
Racing = Dangerous Impacts
6 to 10 times more severe than highway
impacts
18. Midwest Roadside Safety Facility
Research Objective/Design Considerations
• Improve safety for high-energy crashes into
containment walls
120–150 mph & 20-25 degrees
• Design
Extend impact event, absorb kinetic energy, lower
impact forces
Reduce vehicle decelerations
• Sponsored by IMS, IRL, and NASCAR
19. Midwest Roadside Safety Facility
Steel And Foam Energy Reduction (SAFER)
Barrier
Steel Tubular Panel
Trapezoid Foam Blocks
Nylon Straps
22. Midwest Roadside Safety Facility
Different Applications of SAFER Barrier
SAFER emergency gate
SAFER Barrier with alternative backup
structure
SAFER Barrier on Portable Concrete
Barriers (PCB)
23. Midwest Roadside Safety Facility
Key Concepts
Math (calculus for AP credit if possible)
Chemistry (physical/chemical properties)
Physics (forces, moments, gravitational
forces, energy, pressure)
Drafting (AutoCAD, SolidWorks)
Computer literacy
Technical report writing
24. Midwest Roadside Safety Facility
Key Concepts
Presentation skills (public speaking)
Working in teams
Creativity
Be aware of environmental impacts
25. Midwest Roadside Safety Facility
Curriculum Ideas
SAFER Barriers
Computer activities
Drafting
Computer simulation games
Newton’s law activities (F=ma)
Point load vs. distributed load (penny boat
activity)
Put a budget on projects
26. Midwest Roadside Safety Facility
Curriculum Ideas
Work in teams
Make students present their ideas
Question their ideas
Why does/doesn’t this work?
If you could redesign it, what would you
change?
Why did you choose to do it this way?
Is there a better/cheaper way?
Editor's Notes
Dr. Edward R. Post left the Texas Transportation Institute (TTI) of Texas A&M University to join the Civil Engineering Faculty in Lincoln, NE. One of the components of TTI is testing roadside safety equipment, so Dr. Post introduced that idea to UNL upon his arrival.Started as a very small research program sponsored by local government agencies, such as Nebraska Department of Roads (NDOR).In the mid- to late 1980s, they gained the support of a few State highway agencies as well as the Federal Highway Administration (FHWA) and the Forest Products Laboratory (FPL).Then in 1990 in order to gain a better identity, the research group named itself Midwest Roadside Safety Facility.Next, a few midwestern states recognized the need for improved roadside safety equipment. Later, the concept of State Department of Transportations annually funding a research group for the improvement of roadside safety equipment was conceived. As a result of this idea, UNL teamed up with the DOTs of Nebraska, Kansas, and Missouri to form the Midwest State’s Regional Pooled Fund Program. This Pooled Fund program has continued to grow over the years and the program now has thirteen states from both coasts and areas in between.While the research program was beginning to break ground and really take off, MwRSF suffered a loss with the passing of its director Dr. Post in the spring of 1991. This resulted in the search of a new director to lead the group into the future.The hiring of the new director, Dr. Sicking came in 1992 also from TTI. This hiring led to a new focus for MwRSF and it began to emerge as an international leader in the development of new roadside safety hardware instead of strictly testing standard hardware.
The main sponsors of the research that MwRSF does are the State DOTs (mostly through the Pooled Fund Program), the Federal Highway Administration, some private industries, and the Motorsport Industries.
That is around 12,000 run off road accidents and fatalities. That is the area that we focus on reducing through our research. If we can reduce that number by improving roadside safety hardware, then we can view our research as successful.
While these numbers are great and we are happy for the improvement of roadside safety equipment and reduction of fatalities per vehicle mile, I think I can speak for everyone at Midwest when I say that we wont be satisfied until there are no fatalities due to run off road accidents. That’s why we do this research and will continue to do this research well into the future.
Basically anything you see on the side of the road or in the median is something that MwRSF could test for driver safety
If a test passes all of these criteria, the test can pass. If a test fails one of these categories, the test will fail overall.
MASH is the Manual for Assessing of Safety Hardware and it sets the parameters and limits that we must pass in order for test to be deemed a success. For the cable median barrier to be passed for implementation, we must test the system in several different locations in the V-ditch. This picture is a picture of the original design with the brackets to hold the cables. The design was not considered sufficient and has been redesigned to use a keyway system to hold and release the cables. The design has yet to be perfected and research continues to find the best design.
With this system, there have been 7 tests:The first test was the video that we just watched with the bracket system to hold and release the cables. It was tested with our pickup test vehicle and passed.The second test was also with the bracket system, but with the small car test vehicle and the system failedThe third test was also with the bracket system and with the small car test vehicle and the system again failed.The fourth test was with the new keyway bolt design with the small car test vehicle, and the system passed.The fifth test was with the keyway bolt with the pickup test vehicle, and the system failed.The sixth test was the first video that we saw with the sedan test vehicle with the keyway bolt on level terrain, but the test failed.There was a seventh test at TTI with the keyway bolt with the small car test vehicle and it failed.Research into this cable median barrier system continues. The keyway bolt is being redesigned and used in component tests in attempt to find the optimal design.Research has been shifted to the 6:1 V-ditch because they want to find a successful system in the less stringent/critical ditch first.
This system was very successful for the large sedan in the early 1960s and worked successfully for over a quarter of a century.However, with the evolution of the vehicle fleet and the movement toward larger SUV type of vehicles, MwRSF found it worthy of conducting research into redesign of this standard system
These higher center of gravity vehicles had a tendency toward override of the system or forcing a rail rupture.
The goal of the redesign to the standard w-beam guardrail was to develop a non-proprietary w-beam guardrail system in order to make it available to all states.They also wanted to eliminate the weaknesses of the standard w-beam guardrail with their redesign.The increase of the rail height helped to capture the larger center of gravity vehicles and to lower the embedment depth to keep the system from being too stiff.The increase of the blockout depth prevented the vehicle from contacting the posts for a longer period of time to prevent snagging on the posts. The movement of the rail splices away from the posts helped to prevent rupture of the rail because they were no longer at the point of the most force.
Another important part of what we do at MwRSF is computer simulations. We don’t only do full-scale testing of systems. We do quite a bit of computer simulations.These simulations are helpful for several different reasons.
Subsequently, the Midwest Roadside Safety Facility, sponsored by IMS and IRL, and later joined by NASCAR, was asked to develop a new high-speed crash barrier that would improve the crash performance over existing systems for both 2,000-lb open wheel and 3,600-lb stock car vehicles. The development effort was to proceed using the target impact conditions which ranged between 120 and 150 mph and 20 to 25 degrees. These conditions were based on information obtained from real-world crash events as well as guidance from both the IRL and NASCAR.Design considerations for this new barrier included that the new barrier must: be capable of reducing lateral decelerations without significantly increasing longitudinal decelerations as a result of vehicle gouging and snag into the barrier be modular in design in order to increase constructability not require significant down time for making repairs following a crash event remain intact following an extreme crash event and not result in debris scattered across the track