Transportation Safety Technologies, Inc.
Mark W. Arndt, President
Testing is our Specialty
Specialized testing capabilities include full scale vehicle handling and rollover stability testing utilizing a steering robot and instrumentation consistent with recommended practice or standards. Test programs evaluating vehicle pre-crash performance include J-turns, circle turns, obstacle avoidance and other common tests including the National Highway Traffic Safety Administration’s (NHTSA’s) constant speed slowly increasing steer, fishhook and sine with dwell maneuvers. Evaluations include objective measures of vehicle performance under circumstances of different tires/wheels, vehicle load, aftermarket equipment and alternative designs. Tests cover a variety of motorized vehicle components including tests of suspension components, tires, Electronic Stability Control (ESC), door latches, brakes and fuel tanks and related components.
Abstracts
Electronic Stability Control (ESC) with Separated Rear Tire
Electronic Stability Control (ESC) with Separated Rear Tire has the potential of improving yaw stability and reducing the occurrence of a crash when a vehicle experiences a rear tire tread separation. Two instrumented 4-door, RWD SUV’s equipped with ESC were tested to evaluate the effectiveness of their ESC systems on maintaining yaw stability under these circumstances. Tests were run with the ESC engaged and then repeated with the ESC disengaged. An analysis of the data collected shows that there are significant differences in the steering input required to generate a loss of control response with and without ESC enabled. Results of Sine with Dwell testing demonstrate a significant reduction in vehicle spinout response with the ESC engaged. This will likely have a positive effect on a driver’s ability to maintain control when faced with a rear tire tread separation under real world circumstances.
Electronic Stability Control (ESC)
Electronic Stability Control (ESC) effect on SUV Rollover and Handling Stability was evaluated using a first generation ESC equipped 2004 Mercury Mountaineer. Fishhook and Sine with Dwell tests were conducted with the ESC turned off and the ESC turned on. Even with ESC turned on the 2004 Mercury Mountaineer tipped up in Fishhook testing and responded with spinout in the Sine with Dwell testing. Follow-up comparison testing with the Ford corporate twin, 2005 Ford Explorer equipped with second generation ESC (Roll Stability Control, RSC), demonstrated successful completion of both test including tests with maximum roof load and load that caused a maximum rear weight bias (at the GRAWR).
Police Cruiser Rear Collision
The CVPI performance in standard testing and assessments was contrasted to the CVPI’s real world performance in which a series of highly publicized crashes resulted in punctures of the fuel tank and burn injuries and burn deaths and to police officers. Evaluations of real world crashes reveal vehicle defects that were addressed in part by Ford through a variety of remedial design related mechanism including service bulletins, retrofits, design changes and accessory safety equipment. High-speed 50% offset 75 mph car-to-car crash tests, test and analysis at crash severity well in excess of government safety standards, are conducted to validate and evaluate potential remedies of the vehicle’s defects. Standardized testing used in assessing fuel system performance of the Ford CVPI police car was identified as an incomplete indicator of the fuel system’s actual crash performance.
A series of tests were conducted utilizing a tire test machine built to measure forces during a tire tread separation event. Tires were prepared by cutting between the two steel belts inward from the shoulder area. Cuts were varied in size and location to generate different types of tread separation events (eg: long, short, partial, inboard, and outboard). The tests document the longitudinal and lateral forces generated while the tread was detaching during different types of tread separation events. The results demonstrate that magnitude and duration of forces depend upon the nature of the tread separation event. Additional documentation includes high speed and real time video of the tread separation events to provide insights into tread detachment modes and mechanisms of measured force response.
A tire was modified by removing the tread and outer belt with the intended purpose of creating a tire that had suffered a complete tread detachment. This modified tire was mounted on the test vehicle and a series of handling tests performed. From these tests some conclusions can be expressed (from SAE Paper 99-01-0120):
· If the separated tire was on the back of the vehicle and the vehicle was turned away from the tire, the vehicle exhibited dramatic oversteer characteristics and was unstable.
· If the separated tire was on the back of the vehicle and the vehicle was turned towards the tire, the vehicle exhibited less understeer and was generally stable. Overall the behavior was asymmetric.
· In avoidance situations, the vehicle required greater steer inputs and produced significantly different vehicle responses if the modified tire was on the rear axle.
In the video [connected to this case] a 1996 Ford Explorer is driven up to speed, the throttle is dropped and a 180 degree left J-turn is executed. The vehicle on the left is equipped with four good tires. The vehicle on the right is equipped with a right rear tire modified to simulate a tire tread separation – resulting in a spinout response in the J-turn test.
Effective slack associated with seat belt systems for rollover protection is studied for the purpose of improving or anticipating improvements to a motor vehicle rollover protection system. Test methods and test devices were constructed to study and develop objective understandings of the effects of motor vehicle seat and seat belt characteristics on effective slack.
A common feature of fuel caps was the ability of the cap handle/cover to breakaway in collisions while allowing the body of the cap to remain sealed onto the end of the fill pipe. Such a cap was called a breakaway cap. The breakaway feature allows the end of the fuel pipe to move into and around the car body during collisions without generating forces on the sealing mechanism of the fuel cap that might allow fuel leakage. This feature is particularly important in collisions involving rollover when the likely source of spilled gasoline was out the fuel tank fill pipe. Simple instrumented tests document the performance of a variety of caps under conditions of low force induced torque on the cap handle/cover. In some instances caps leak before the cap handle/cover breaks away while other caps perform properly and breakaway before leaking. A recent innovation observed on some Ford vehicles eliminated the fuel cap and provided a refueling port that opened upon insertion of the gas filling station nozzle and self sealed upon its removal.
An AB Dynamics Steering Robot was utilized in controlled and instrumented test conducted pursuant to the National Highway Traffic Safety Administration’s (NHTSAs) New Car Assessment Program’s (NCAP) fishhook test protocol. Successful design changes validated by the NHTSA’s fishhook test protocol have been performed on a Chevrolet Blazer, Ford Explorer Sport, Mitsubishi Montero Sport, Chevrolet Tracker and 2004 Ford Explorer. Sample results include:
Explorer tipping up. This is a test of the vehicle with water dummies or equivalent belted in the RF and rear seat (two in the rear seat)
Safer design NOT tipping up. This test was configured with P205/75R15 tires and had a modified track width increased by four inches and the center of gravity lowered by one inch.
Full Scale Vehicle Rollover was developed as a demonstration under the auspices of Southwestern Association of Technical Accident Investigators, Inc. (SATAI). Transportation Safety Technologies, Inc. developed and utilized capability that will remotely drive any vehicle, produce steering that may induce rollover and record, through calibrated instruments, pre rollover conditions and rollover response. The capability includes the first know special mechanisms developed that synchronize the visual, electronic and physical characteristics of the test and provide a redundant safety system for aborting the test if necessary.