Roadside Safety and Physical Security

Design, Testing & Performance Evaluation

Research Areas

The Roadside Safety and Physical Security Division has seven main research areas:

Roadside Safety

ET guardrail end treatment

Revolutionizing the science behind safer guardrail terminals, the energy absorbing ET (Extruder Terminal) is recognized around the world as a pivotal transportation safety innovation. Hundreds of thousands have been installed worldwide, saving an untold number of lives each year. This technology is continues to be tested and updated to ensure that the ET meets current safety standards.

HEART™ roadside crash cushion

Years were spent on design and testing, yet it only takes a split second to smash into it. The similarities between the Hybrid Energy Absorbing Reusable Terminal (HEART) crash cushion and other crash cushions stops there. The HEART is reusable and was designed for high accident locations, where frequent crash-cushion replacement generates significant expense, traffic delay, and exposure of maintenance personnel.

Slotted Rail Terminal (SRT) 350™

The SRT was introduced in January 1995 as a guardrail end treatment. The SRT technology consists of cutting small slots in the ridges of the w-beam in a guardrail, thus converting the beam into four plates. The slots create weak points in the beam that cause the guardrail to buckle at predetermined locations if it is hit by a vehicle.

WY-BET™ End Treatment

The WY-BET (Wyoming Box-beam End Terminal) end treatment is constructed of box beam (tubular) rail. When hit, the end piece slides over the next section of box beam and absorbs the kinetic energy of the errant vehicle. In full-scale crash testing, vehicles were brought to a safe stop, meaning enhanced safety for car or truck occupants.

Slip-Safe™ Breakaway Sign Coupling

The Slip-Safe is a breakaway sign coupling developed by engineers at TTI and is the only true 360° u-channel breakaway system available with built-in advanced safety and reusable components. In most cases, the base post, attachment hardware, castings and top post are reusable. Slip-Safe is designed to handle both small and medium size sign supports.

Physical Security

Shallow mount bollard

Embassies and other security-sensitive locations are increasingly being built in urban areas where something previously stood. The utilities at the perimeter of these properties—where sidewalks and streets are located—may be buried within 2 ft. of the surface. Previously, bollards had to be mounted deeper than 2 ft. to stop vehicles from crashing into sensitive buildings. Sandia National Laboratories and the U.S. Department of State teamed with TTI to design and successfully crash test a shallow mount bollard that can be installed in an 18- inch deep concrete foundation.

Computational Mechanics

Crash test modeling and analysis

Researchers in TTI‘s Center for Transportation Computational Mechanics (CeTCoM) apply state-of-the-art analytical tools such as LS-DYNA to accurately model crash tests on the computer. Increasingly detailed finite element models are used in impact simulations to predict how vehicles and safety devices perform in collisions. Dedicated high-speed computing facilities enable these large simulations to be run in a short period of time. These sophisticated analysis techniques enable researchers to design better, more cost-effective safety hardware at a lower cost to the sponsor.

Instrumentation and Control Systems

Customizable components

TTI researchers are capable of crash testing an 80,000-lb. truck by remote control. Every aspect of vehicle control and safety, including steering, brakes, throttle, clutch and a fail-safe shutdown system are custom crafted for each distinct vehicle being crashed. Researchers also design unique devices for testing where a device simply does not exist, like a control and data system to perform accelerated life cycle testing of vehicle-mounted wheelchair ramp mechanisms.

Roadway Friction Measurement

Calibrating to national standards

TTI is one of only two agencies nationwide that calibrate and evaluate friction measurement systems. Visiting systems are statically and dynamically tested and adjusted to comply with ASTM standard E274. TTI’s Proving Ground has one of only two E274 Area Reference Friction Measurement Systems (ARFMS) in the country, as well as various asphalt and concrete test surfaces. Since the mid 1970’s, over 430 calibrations of state friction systems from throughout the U.S. have been performed.

Adaptive Vehicle Control

Safety and mobility for disabled drivers

Advancements in design, technology and imagination are making it possible for drivers with a host of physical disabilities and other challenges to enjoy the freedom and independence of driving. The Texas Department of Assistive and Rehabilitative Services (DARS) utilizes engineering safety experts at TTI to ensure that vehicles modified for disabled drivers are safe. Additionally, TTI inspects modified vehicles to ensure equipment is installed properly, the vehicle is structurally sound and safety is not compromised due to modifications of the accelerator, brake and other vehicle components.

Structural Testing

Finding limits, ensuring standards

Researchers at TTI evaluate key components of safety devices and the affect they have on the performance of the system. Static load tests and dynamic impact tests are performed using gravitational pendulums and reusable surrogate vehicles to determine load response and performance limits of components and systems. These data are used in the design of roadside safety and perimeter security hardware devices and validation of computer models.