Garrick Forkenbrock

An Experimental Examination of J-Turn and Fishhook Maneuvers That May Induce On-Road, Untripped Light Vehicle Rollover

In this chapter, from a comprehensive text about occupant and vehicle responses in rollovers, the authors report on an experimental examination of J-turn and fishhook maneuvers that may induce on-road, untripped, light vehicle rollover. This chapter is the first of two papers on the research used to develop dynamic maneuver tests for rollover resistance ratings. This research was part of the National Highway Traffic Safety Administrations (NHTSA) rollover research program (2001). In this phase of research, five characterization maneuvers and eight rollover resistance maneuvers were evaluated and assigned a rating of Excellent, Good, Satisfactory, Bad, or Very Bad. This chapter offers an analysis of one characterization maneuver (the Slowly Increasing Steer maneuver) and four Rollover Resistance maneuvers (the NHTSA J-Turn, Fishhook 1a, Fishhook 1b, and Nissan fishhook). Results determined that each of these maneuvers has a rating of satisfactory or better in each of the maneuver evaluation factors (objectivity and repeatability, performability, discriminatory capability, and appearance of reality). The authors rated Fishhook 1b the best overall; however, since the NHTSA J-Turn is the most basic of potential maneuvers, they feel it serves as a useful complement to Fishhook 1b.

Driver Crash Avoidance Behavior with ABS in an Intersection Incursion Scenario on Dry Versus Wet Pavement

ABSTRACTThe National Highway Traffic Safety Administration(NHTSA) has developed its Light Vehicle Antilock BrakeSystems (ABS) Research Program in an effort todetermine the cause(s) of the apparent increase in fatalsingle-vehicle run-off-road crashes as vehicles undergo atransition from conventional brakes to ABS. As part of thisprogram, NHTSA conducted research examining drivercrash avoidance behavior and the effects of ABS ondrivers’ ability to avoid a collision in a crash-imminentsituation. The study described here was conducted on atest track under dry and wet pavement conditions toexamine the effects of ABS versus conventional brakes,ABS brake pedal feedback level, and ABS instruction ondriver behavior and crash avoidance performance. Thisstudy found that drivers do tend to brake and steer inrealistic crash avoidance situations and that excessivesteering can occur . However, a significant number of roaddepartures did not result from this behavior for eitherpavement condition. ABS was found to reduce crashessignificantly on wet pavement as compared to conventionalbrakes.INTRODUCTIONSince 1985, antilock brake systems (ABS) have beenincreasingly available on many passenger car and lighttruck make/models. ABS have been sold as an addedsafety feature which enhances drivers’ ability to control avehicle and, in some cases, improves vehicle stoppingperformance. In the interest of reaping the benefits ofABS in terms of a reduction in crashes, the HighwaySafety Act of 1991, Section 2507 charged the NationalHighway Traffic Safety Administration (NHTSA) with thetask of determining whether ABS should be required on allpassenger vehicles.As a result, NHTSA undertook a series of investigations todetermine the potential benefits of ABS and the effect ofABS on crash rates. Test programs have shown that ABSappear to be very promising safety devices whenevaluated on a test track. Under many pavementconditions antilock brake systems allow the driver to stopa vehicle more rapidly while maintaining steering controleven during situations of extreme, panic braking. Brakeexperts anticipated that the introduction of ABS onpassenger vehicles would reduce both the number andseverity of crashes. However, a number of crash dataanalyses have been performed in recent years by NHTSA,automotive manufacturers, and others which indicate thatthe introduction of ABS has not been found to beassociated with a reduction in crashes to the expectedextent. CRASH DATAKahane [1] found that, with the introduction of ABS,involvements in mutli-vehicle crashes involving fatalities onwet roads were significantly reduced by 24 percent, andnonfatal crashes by 14 percent. However, thesereductions were offset by a statistically significant increasein the frequency of single-vehicle, run-off-road crashes, ascompared to cars without ABS. Run-off-road crashes, asconsidered in this report, included rollovers, side impactswith fixed objects , and frontal impacts with fixed objects.Fatal run-off-road crashes were up by 28 percent andnonfatal crashes by 19 percent. On wet roads, fatal run-off-road crashes increased 17 percent and non-fatal run-off-road crashes increased by 24 percent. On dry roads,fatal run-off-road crashed increased by 29 percent whilenon-fatal crashes increased by 17 percent.Hertz, Hilton, and Johnson [2] presented results forpassenger car run-off-road crashes according to thefollowing crash types: rollovers, side impacts with parkedvehicles or fixed objects, and frontal impacts with parkedvehicles or fixed objects. For dry roads, ABS was found tobe associated with a 17 percent decrease in rollovercrashes, a 13 percent decrease in frontal impacts withparked vehicles or fixed objects, and a 7 percent increasein side impacts with parked cars or fixed objects. Forpedestrian crashes, ABS was associated wtih a 30 percentreduction on dry roads and a 10 percent reduction inunfavorable road conditions (i.e., wet, snowy, icy, gravel).In regards to only those crashes involving fatalities, ABSwas found to be associated with a 51 percent increase infatal rollover crashes on dry roads. For fatal side impact

An Experimental Examination of Double Lane Change Maneuvers That May Induce On-Road, Untripped, Light Vehicle Rollover

This paper gives an account of the research used to develop maneuver tests for rollover resistance ratings. The paper discusses test procedures and results for five characterization maneuver and eight rollover resistance maneuvers. Each rollover resistance maneuver was evaluated based on its objectivity and reliability, performability, discriminatory capability, and appearance of reality. The objective of this paper was to obtain the data needed to select a limited set of maneuvers capable of assessing light vehicle rollover resistance.

Results from NHTSA's experimental examination of selected maneuvers that may induce on-road untripped, light vehicle rollover

A main goal of the National Highway Traffic Safety Administration (NHTSA) is to reduce the number of fatalities and injuries due to rollover crashes. To achieve this goal, the NHTSA is conducting research programs both to reduce the number of rollover crashes that occur and to mitigate the adverse consequences when rollover crashes do occur. To reduce the number of rollover crashes, the NHTSA is working to develop either an information program, which will make consumers more aware of vehicle makes/models with high rollover rates, or a Federal Motor Vehicle Safety Standard (FMVSS), which would prevent the manufacture of vehicles that have too high a rollover propensity, or both. One key step in the development of either a rollover propensity consumer information program or a rollover propensity FMVSS would be to construct a methodology for determining a vehicles rollover propensity. This study focuses on the development of such a methodology.

A Comprehensive Light Vehicle Antilock Brake System Test Track Performance Evaluation

To determine if situations and/or conditions exist in which ABS-equipped vehicles do not perform as well as those without ABS, the braking performance of nine passenger vehicles was observed over a comprehensive array of driving conditions. For most maneuvers, on most surfaces, ABS-assisted stops yielded distances shorter than those made with the ABS disabled. The one exception was on loose gravel where stopping distances increased by an average of 27.2 percent overall. Additionally, the vehicular stability observed during testing was almost always superior with ABS. For the cases in which instability was observed, ABS was not deemed responsible for its occurrence.

Effects of Outriggers on Dynamic Rollover Resistance Maneuvers - Results from Phase V of NHTSA's Light Vehicle Rollover Research Program

This paper describes the National Highway Traffic Safety Administrations (NHTSA) efforts to determine how different outrigger designs can affect J-Turn and Road Edge Recovery test maneuver outcome. Data were collected during tests performed with three different outrigger designs (made from aluminum, carbon fiber, and titanium) having different physical properties (geometry and weight). Four sport utility vehicles were tested: a 2001 Chevrolet Blazer, 2001 Toyota 4Runner, 2001 Ford Escape, and a 1999 Mercedes ML320. The 4Runner and ML320 were,each equipped with electronic stability control, however the systems were disabled for the tests performed in this study. A detailed description of the testing performed and the results obtained are discussed. From the results, a comparison of how the three outrigger designs affected the test results is provided.