Background to NHTSA NCAP Ratings for Rollover Resistance Why are they based on Static Stability Factor?

Criticism of Rollover RatingsVehicle properties have little effectStatic Stability Factor (SSF) is too simplisticSSF does not reward Electronic Stability Control (ESC)Rollover ratings should be on dynamic testsRollover ratings will confuse customers

What This Presentation AddressesWhy we think vehicle properties affect rolloverRequirements for a rollover rating systemEvaluation of several laboratory metricsOur measure of rollover risk ro/svcThe problem of rewarding ESCObservations about dynamic maneuver tests

Overview of Vehicle Effect

Cars

Vans

Pickup Trucks

SUVs

Rollovers as a % of

All Crashes

1.6 %

2.0 %

3.7 %

5.1 %

Rollovers as a % of Single Veh.

Crashes

13 %

14 %

24 %

32 %

MeanDummy

With 25 & 250 Thresholds

FL1.225345,46655,709

MD0.693322,92515,894

MO0.000040,9000.0

NC0.696958,44940,733

PA1.244948,72060,652

UT0.86229,6578,326

Total226,117181,314

Average0.8019

Without 25 & 250 Thresholds

FL1.346745,61961,435

MD0.738223,10117,053

MO0.000041,0300.0

NC0.729658,58442,743

PA1.332248,86165,093

UT0.87859,9998,784

Total227,194195,108

Average0.8588

&C&F&R&D

LinearResults

AVERAGE OVER SIX VIN STATES

Rates produced by rncap_states6_national.sas

Modeled

Single-OriginalAdjustedAverageAverageRollRate

VehicleRolloverRolloverUnadjustedAdjusted2.5860

MODELTYPESSFStatesSampleSampleEstimateRollRateRollRate-3.3760

1car1.4463,2874443210.13510.09780.1028

2car1.42691060930.06590.10200.1099

3car1.3868,7311,5291,1020.17510.12620.1258

4car1.3769831701320.17290.13480.1301

5car1.3867,4738667630.11590.10210.1258

6car1.4162,0822281630.10950.07850.1137

7car1.4569,1339421,0030.10310.10980.0993

8car1.4461,483831310.05600.08820.1028

9car1.3866,6857578720.11320.13040.1258

10car1.4165,2529248270.17590.15740.1137

11car1.3451,1031711760.15500.15920.1440

12car1.3961,6811882340.11180.13940.1216

13car1.385728711170.09750.16090.1258

14car1.3565,3089777770.18410.14640.1392

15car1.3866,6661,1239410.16850.14110.1258

16car1.5364,3404003300.09220.07610.0758

17car1.5065,0134473870.08920.07720.0839

18car1.4051,664781630.04690.09770.1176

19car1.32610,6911,8001,3810.16840.12920.1541

20car1.3064,7867997170.16690.14980.1648

21car1.3262,8046915070.24640.18070.1541

22car1.2969992411810.24120.18110.1705

23car1.3962,1924163320.18980.15170.1216

24car1.356573101750.17630.13080.1392

25car1.3862,0053932470.19600.12310.1258

26car1.4863,9044903410.12550.08740.0898

27car1.4361,150131920.11390.07980.1063

28car1.4764,8026295720.13100.11910.0929

29car1.40556766600.11640.10650.1176

30car1.4461,8682312370.12370.12690.1028

31car1.4663,4605173650.14940.10540.0960

32car1.4061,2001871350.15580.11230.1176

33car1.4663,7224794630.12870.12430.0960

34car1.3662,5033853180.15380.12720.1346

35car1.4161,5612881910.18450.12220.1137

36car1.395640101710.15780.11050.1216

37suv1.13310425410.24040.39690.2926

38suv1.1361,1582943600.25390.31060.2926

39suv1.0435182862370.55210.45780.3965

40suv1.0461,5506856670.44190.43020.3965

41suv1.0751,1994744840.39530.40410.3583

42suv1.0863,2481,0431,1220.32110.34550.3464

43suv1.0638853773870.42600.43680.3706

44suv1.0661,4625475840.37410.39970.3706

45suv1.1051,1734634960.39470.42300.3238

46suv1.1064,1061,2651,3580.30810.33070.3238

47suv1.0923441681560.48840.45340.3349

48suv1.0961,2754554650.35690.36480.3349

49suv1.096278951010.34170.36200.3349

50suv1.1265221561700.29890.32580.3027

52suv1.08413126310.19850.23710.3464

53suv1.1362,3008936440.38830.28000.2926

55suv1.0667262602590.35810.35630.3706

56suv1.0265602762680.49290.47950.4242

57suv1.07415072840.48000.56240.3583

58suv1.0863,3421,0761,1330.32200.33910.3464

60suv1.0761,7515676130.32380.35010.3583

61suv1.2062,4528207650.33440.31200.2310

62suv1.0768472872960.33880.34920.3583

63suv1.1013913140.33330.36270.3238

64suv1.0953601431330.39720.37000.3349

65suv1.0061,1105555730.50000.51590.4538

66suv1.066291110950.37800.32680.3706

67van1.2166,7181,1431,4090.17010.20970.2234

68van1.2368861001410.11290.15950.2088

70van1.1063,7929321,1000.24580.29020.3238

73van1.246632801030.12660.16240.2018

74van1.1262,9796177920.20710.26590.3027

75van1.1261,1522302550.19970.22170.3027

77van1.0869391963200.20870.34120.3464

78van1.1766741251470.18550.21830.2557

79van1.23531855680.17300.21510.2088

80p/u1.25316220220.12350.13440.1951

81p/u1.2259211261910.13680.20770.2159

82p/u1.28528530520.10530.18230.1764

83p/u1.1965,1967511,0650.14450.20490.2390

84p/u1.1563,7108049050.21670.24390.2735

85p/u1.185578861340.14880.23120.2472

86p/u1.1364,8241,5581,6190.32300.33560.2926

87p/u1.0361,6537427150.44890.43280.4101

88p/u1.1766,0481,6491,6210.27270.26810.2557

89p/u1.0761,4895915470.39690.36710.3583

90p/u1.2265,1237019990.13680.19510.2159

91p/u1.1464,0809491,0030.23260.24590.2829

92p/u1.1965,8221,3011,3790.22350.23690.2390

93p/u1.1969092552540.28050.27990.2390

94p/u1.1464,0458709620.21510.23780.2829

95p/u1.1454941411480.28540.30060.2829

96p/u1.2062,9336947200.23660.24560.2310

97p/u1.1161,0443653080.34960.29470.3131

98p/u1.2361,9183783900.19710.20310.2088

99p/u1.0762,5801,1651,0000.45160.38760.3583

100p/u1.26438386910.22450.23650.1887

Total6226,11745,57444,8130.20160.1982

&C&F&R&D

LinearPlot-1

0.1351

0.0659

0.1751

0.1729

0.1159

0.1095

0.1031

0.056

0.1132

0.1759

0.155

0.1118

0.0975

0.1841

0.1685

0.0922

0.0892

0.0469

0.1684

0.1669

0.2464

0.2412

0.1898

0.1763

0.196

0.1255

0.1139

0.131

0.1164

0.1237

0.1494

0.1558

0.1287

0.1538

0.1845

0.1578

0.2404

0.2539

0.5521

0.4419

0.3953

0.3211

0.426

0.3741

0.3947

0.3081

0.4884

0.3569

0.3417

0.2989

0.1985

0.3883

0.3581

0.4929

0.48

0.322

0.3238

0.3344

0.3388

0.3333

0.3972

0.5

0.378

0.1701

0.1129

0.2458

0.1266

0.2071

0.1997

0.2087

0.1855

0.173

0.1235

0.1368

0.1053

0.1445

0.2167

0.1488

0.323

0.4489

0.2727

0.3969

0.1368

0.2326

0.2235

0.2805

0.2151

0.2854

0.2366

0.3496

0.1971

0.4516

0.2245

Unadjusted

SSF

Rollovers per Single-Vehicle Crash

Figure 1: Rollovers per Single-Vehicle Crash Estimated from Six States(Not Adjusted for Differences in Road Use or State Reporting)

LinearPlot-2

0.09780.1027516877

0.1020.1099290633

0.12620.1258228895

0.13480.1301431865

0.10210.1258228895

0.07850.1137036246

0.10980.0993406923

0.08820.1027516877

0.13040.1258228895

0.15740.1137036246

0.15920.1440146858

0.13940.1216460111

0.16090.1258228895

0.14640.1392339037

0.14110.1258228895

0.07610.075828581

0.07720.0839108796

0.09770.1176077905

0.12920.1540743501

0.14980.1648366987

0.18070.1540743501

0.18110.170496587

0.15170.1216460111

0.13080.1392339037

0.12310.1258228895

0.08740.0897721936

0.07980.1062798042

0.11910.0928546418

0.10650.1176077905

0.12690.1027516877

0.10540.09604293

0.11230.1176077905

0.12430.09604293

0.12720.1346118267

0.12220.1137036246

0.11050.1216460111

0.39690.2926201288

0.31060.2926201288

0.45780.3965155581

0.43020.3965155581

0.40410.3583231665

0.34550.346428095

0.43680.3706266712

0.39970.3706266712

0.4230.3238094673

0.33070.3238094673

0.45340.3349278981

0.36480.3349278981

0.3620.3349278981

0.32580.3026676319

0.23710.346428095

0.280.2926201288

0.35630.3706266712

0.47950.4242128267

0.56240.3583231665

0.33910.346428095

0.35010.3583231665

0.3120.2310317805

0.34920.3583231665

0.36270.3238094673

0.370.3349278981

0.51590.4538447953

0.32680.3706266712

0.20970.2233623362

0.15950.2087787918

0.29020.3238094673

0.16240.2018480686

0.26590.3026676319

0.22170.3026676319

0.34120.346428095

0.21830.2556566361

0.21510.2087787918

0.13440.1951474212

0.20770.2159474906

0.18230.1763508151

0.20490.2389645654

0.24390.2735146756

0.23120.2471697331

0.33560.2926201288

0.43280.4101304497

0.26810.2556566361

0.36710.3583231665

0.19510.2159474906

0.24590.2829061675

0.23690.2389645654

0.27990.2389645654

0.23780.2829061675

0.30060.2829061675

0.24560.2310317805

0.29470.3130601295

0.20310.2087787918

0.38760.3583231665

0.23650.1886692117

Adjusted

RollRate

SSF

Rollovers per Single-Vehicle Crash

Figure 2: Rollovers per Single-Vehicle Crash Estimated from Six States(Adjusted to National Average Road Use and for Differences in State Reporting)

Estimates

AVERAGE OVER SIX VIN STATES

Model 1 results shown in earlier worksheet (LinearResults)

Models 2-5 results shown in earlier worksheet (LogisticResults)

Model 2:

Expected

Model 1Model 2Model 3Model 4Model 5Rollovers

Model 2:in

SummarizedCombinedAveragedCombinedAveragedObservedExpectedSingle-

Data,Data,Data,Data,Data,RolloversRolloversVehicle

LinearIndividualIndividualCrashCrashObservedininCrashes

ModelVariables,Variables,Scenarios,Scenarios,Single-Single-Single-with 0.02

2.5860LogisticLogisticLogisticLogisticVehicleVehicleVehicleIncrease

SSF-3.3760ModelModelsModelModelsCrashesCrashesCrashesin the SSF

0.950.53730.45430.44580.44200.4334

0.960.51950.44540.43720.43350.4252

0.970.50220.43650.42860.42500.4171

0.980.48550.42770.42010.41660.4090

0.990.46940.41880.41160.40820.4009

1.000.45380.41010.40310.39990.39291,110555455436

1.010.43880.40140.39470.39160.38490.00.0

1.020.42420.39280.38640.38340.3770560276220210

1.030.41010.38420.37810.37530.36921,653742635607

1.040.39650.37570.36990.36720.36142,102989790755

1.050.38340.36730.36180.35920.35370.00.0

1.060.37060.35900.35370.35130.34603,3991,3131,2201,164

1.070.35830.35070.34570.34350.33858,0743,1732,8322,701

1.080.34640.34250.33780.33570.33107,6852,3472,6322,509

1.090.33490.33450.33000.32810.32362,441929817778

1.100.32380.32650.32230.32050.31639,2982,7263,0362,890

1.110.31310.31860.31470.31300.30911,200392382364

1.120.30270.31080.30710.30560.30194,6531,0031,4461,375

1.130.29260.30320.29970.29840.29498,4472,7862,5612,434

1.140.28290.29560.29240.29120.28798,6431,9692,5552,427

1.150.27350.28820.28520.28410.28113,7108041,0691,015

1.160.26440.28080.27800.27710.27430.00.0

1.170.25570.27360.27100.27030.26776,7221,7741,8391,744

1.180.24720.26650.26410.26350.261165399174165

1.190.23900.25950.25740.25680.254711,9752,3183,1082,945

1.200.23100.25260.25070.25030.24845,3851,5141,3601,289

1.210.22340.24590.24410.24390.24216,7181,1431,6521,564

1.220.21590.23930.23770.23760.23606,0608321,4501,372

1.230.20880.23280.23140.23140.23003,137540730690

1.240.20180.22640.22520.22530.224163280143135

1.250.19510.22010.21910.21930.2183194214340

1.260.18870.21400.21320.21340.2126407938782

1.270.18240.20800.20740.20770.20700.00.0

1.280.17640.20210.20160.20210.2016292335956

1.290.17050.19640.19600.19660.1962999241196185

1.300.16480.19070.19060.19120.19104,786799913861

1.310.15940.18520.18520.18590.18580.00.0

1.320.15410.17990.18000.18070.180813,4952,4912,4282,287

1.330.14900.17460.17490.17560.17590.00.0

1.340.14400.16950.16990.17070.17111,123179190179

1.350.13920.16450.16500.16590.16635,8811,078967910

1.360.13460.15960.16020.16110.16172,503385399376

1.370.13010.15480.15560.15650.1572983170152143

1.380.12580.15010.15100.15200.152832,3054,7404,8494,561

1.390.12160.14560.14660.14760.14864,535716660620

1.400.11760.14120.14230.14330.14443,467337490460

1.410.11370.13680.13810.13910.14038,8951,4401,2171,143

1.420.10990.13260.13400.13500.136391060121113

1.430.10630.12850.13000.13100.13241,150131148139

1.440.10280.12460.12610.12720.12866,638758827776

1.450.09930.12070.12230.12340.12499,1339421,1021,034

1.460.09600.11690.11860.11970.12137,182996840788

1.470.09290.11320.11500.11610.11784,802629544510

1.480.08980.10970.11150.11260.11433,904490428401

1.490.08680.10620.10810.10920.11100.00.0

1.500.08390.10280.10480.10590.10785013447515483

1.510.08110.09950.10160.10260.10460.00.0

1.520.07840.09640.09850.09950.10150.00.0

1.530.07580.09330.09550.09650.09854340400405379

1.540.07330.09030.09250.09350.09560.00.0

1.550.07090.08730.08960.09060.09280.00.0

Risk Ratio6.04.44.24.14.045,88048,68646,098

SSF=1.00

versus5.3%

SSF=1.53

&C&F&R&D

ModelPlots

0.45384479530.41010.40310.39990.3929

0.43877874090.40140.39470.39160.3849

0.42421282670.39280.38640.38340.377

0.41013044970.38420.37810.37530.3692

0.39651555810.37570.36990.36720.3614

0.38335263320.36730.36180.35920.3537

0.37062667120.3590.35370.35130.346

0.35832316650.35070.34570.34350.3385

0.3464280950.34250.33780.33570.331

0.33492789810.33450.330.32810.3236

0.32380946730.32650.32230.32050.3163

0.31306012950.31860.31470.3130.3091

0.30266763190.31080.30710.30560.3019

0.29262012880.30320.29970.29840.2949

0.28290616750.29560.29240.29120.2879

0.27351467560.28820.28520.28410.2811

0.26443494830.28080.2780.27710.2743

0.25565663610.27360.2710.27030.2677

0.24716973310.26650.26410.26350.2611

0.23896456540.25950.25740.25680.2547

0.23103178050.25260.25070.25030.2484

0.22336233620.24590.24410.24390.2421

0.21594749060.23930.23770.23760.236

0.20877879180.23280.23140.23140.23

0.20184806860.22640.22520.22530.2241

0.19514742120.22010.21910.21930.2183

0.18866921170.2140.21320.21340.2126

0.1824060560.2080.20740.20770.207

0.17635081510.20210.20160.20210.2016

0.1704965870.19640.1960.19660.1962

0.16483669870.19070.19060.19120.191

0.15936469880.18520.18520.18590.1858

0.15407435010.17990.180.18070.1808

0.14895962250.17460.17490.17560.1759

0.14401468580.16950.16990.17070.1711

0.13923390370.16450.1650.16590.1663

0.13461182670.15960.16020.16110.1617

0.13014318650.15480.15560.15650.1572

0.12582288950.15010.1510.1520.1528

0.12164601110.14560.14660.14760.1486

0.11760779050.14120.14230.14330.1444

0.11370362460.13680.13810.13910.1403

0.10992906330.13260.1340.1350.1363

0.10627980420.12850.130.1310.1324

0.10275168770.12460.12610.12720.1286

0.09934069230.12070.12230.12340.1249

0.096042930.11690.11860.11970.1213

0.09285464180.11320.1150.11610.1178

0.08977219360.10970.11150.11260.1143

0.08679207180.10620.10810.10920.111

0.08391087960.10280.10480.10590.1078

0.08112533290.09950.10160.10260.1046

0.07843225660.09640.09850.09950.1015

0.0758285810.09330.09550.09650.0985

Model 1

Model 2

Model 3

Model 4

Model 5

SSF

Rollovers per Single-Vehicle Crash

Figure 3: Rollovers per Single-Vehicle Crash Estimated from Six States:Comparison of the Summary and Logistic Approaches

ThreeModels

0.45384479530.41010.3999

0.43877874090.40140.3916

0.42421282670.39280.3834

0.41013044970.38420.3753

0.39651555810.37570.3672

0.38335263320.36730.3592

0.37062667120.3590.3513

0.35832316650.35070.3435

0.3464280950.34250.3357

0.33492789810.33450.3281

0.32380946730.32650.3205

0.31306012950.31860.313

0.30266763190.31080.3056

0.29262012880.30320.2984

0.28290616750.29560.2912

0.27351467560.28820.2841

0.26443494830.28080.2771

0.25565663610.27360.2703

0.24716973310.26650.2635

0.23896456540.25950.2568

0.23103178050.25260.2503

0.22336233620.24590.2439

0.21594749060.23930.2376

0.20877879180.23280.2314

0.20184806860.22640.2253

0.19514742120.22010.2193

0.18866921170.2140.2134

0.1824060560.2080.2077

0.17635081510.20210.2021

0.1704965870.19640.1966

0.16483669870.19070.1912

0.15936469880.18520.1859

0.15407435010.17990.1807

0.14895962250.17460.1756

0.14401468580.16950.1707

0.13923390370.16450.1659

0.13461182670.15960.1611

0.13014318650.15480.1565

0.12582288950.15010.152

0.12164601110.14560.1476

0.11760779050.14120.1433

0.11370362460.13680.1391

0.10992906330.13260.135

0.10627980420.12850.131

0.10275168770.12460.1272

0.09934069230.12070.1234

0.096042930.11690.1197

0.09285464180.11320.1161

0.08977219360.10970.1126

0.08679207180.10620.1092

0.08391087960.10280.1059

0.08112533290.09950.1026

0.07843225660.09640.0995

0.0758285810.09330.0965

Linear Regression Model, Summary Data

Logistic Regression Model, Individual Variables

Logistic Regression Model, Scenario-Risk

SSF

Rollovers per Single-Vehicle Crash

Requirements for Rollover Rating System Represent tripped and untripped rolloversCorrelation with rollover crash statistics Clear causal relationship to rolloverObjective and repeatable measurementsLow potential for unintended consequencesUnderstandable by consumers

Tripped and Untripped Rollover82% of Rollovers are in SVC95% are tripped (curb, soft soil, ditch, guard rail, side slope, rim dig, etc.)

Laboratory MetricsTilt Table Ratio or Centrifuge TestCritical Sliding VelocitySSFHighly cross correlated because of the importance of cg height and track widthEach correlate with crash statistics

Tilt Table Angle (TTA) Minimum table angle at which a vehicle on the table will tip over.

Centrifuge Test Apparatus

Why Not Tilt Table or Centrifuge?Their advantage is measurement of suspension and tire deflection effect Test performance increases when both tires lift simultaneouslyRoll stiffness ratios for best score cause more oversteer than current practicePotential for unintended consequences

Critical Sliding Velocity (CSV)Theoretical minimum lateral speed for tripped rollover:Vehicle Motion

Sheet1

Critical Sliding Velocities of Test Vehicles - Descending Order

MAKE/MODELCSV* (mph)Vehicle Type

Dodge Neon12.9pass. car (compact)

Honda Civic12.7pass. car (compact)

Mazda Protg12.6pass. car (compact)

Nissan Sentra12.4pass. car (compact)

Toyota Tercel12.2pass. car (subcompact)

Chevrolet Lumina12.2pass. car (mid-size)

Saturn SL12.0pass. car (compact)

Mercury Tracer11.9pass. car (compact)

Ford Windstar11.8van (mini-van)

Dodge Caravan11.8van (mini-van)

Dodge Ram 150011.6pick-up, 2WD (full-size)

Plymouth Grand Voyager11.6van (mini-van)

Dodge Dakota11.4pick-up, 2WD (mid-size)

Chevy C150011.3pick-up, 2WD (full-size)

Chevrolet Metro11.1pass. car (subcompact)

Toyota Tacoma11.1pick-up, 2WD (small)

Ford F15011.0pick-up, 2WD (full-size)

Chevrolet Venture11.0van (mini-van)

Isuzu Rodeo10.8SUV, 4WD

Honda CR-V10.8SUV, 4WD

Ford E-150 Club Wagon10.8van (full-size)

Mazda MPV10.7van (mini-van)

Chevrolet Astro10.7van (mid-size)

Chevrolet Tahoe 4dr10.6SUV, 4WD (full-size)

Dodge Durango10.5SUV, 4WD (mid-size)

Nissan Frontier10.3pick-up, 2WD

Ford Expedition10.2SUV, 4WD (full-size)

Chevrolet Suburban10.2SUV, 4WD (full-size)

Chevrolet S1010.0pick-up, 2WD (small)

Nissan Pathfinder9.9SUV, 4WD

Chevrolet Tracker 2dr 4WD9.9SUV, 4WD (compact)

Ford Ranger9.8pick-up, 2WD (small)

Jeep Grand Cherokee9.7SUV, 4WD

Chevrolet Blazer9.7SUV, 4WD

Toyota 4Runner9.6SUV, 4WD

1997 Ford Ranger 4WD9.5pick-up, 4WD

Ford Explorer9.5SUV, 4WD

CSV Critical Sliding Velocity in mph

g gravitational acceleration

Ioxx moment of inertia about tires

Ixx moment of inertia about longitudinal centroidal axis

M test vehicle mass

hcg test vehicle center of gr

MBD000D8F6E.unknown

MBD000DACBE.unknown

Why Not Critical Sliding Velocity?CSV adds the effect of roll moment inertia on tripped rolloversThe rigid body model causes CSV to be less than realistic (range 10 to 15 mph) Increase in CSV through higher roll moment causes theoretical loss of maneuver test performanceConsumer perception is the problem

Static Stability Factor (SSF) - t/2h First order estimate of steady state lateral acceleration at wheel lift

SSF is the Best Choice?Represents 1st order causal influences on rollover - overturning and restoring momentsC.G. height measurement accurate to 0.5% Least possibility of bad trade-offsSimple concept - intuitive to consumersRemaining QuestionsWhat is its correlation to real rollover crashes?How important is its effect?What about untripped rollover?

Adjusted RO/SVC; 220,000 SVC; R2 = 0.88Adjusted to National Avg. Road Use and for Differences in State Reporting

Phase II Rollover Testing* ABS Failure

Sheet1

1808

1526

Width0.40.50.60.70.40.50.60.747008

1402448230593663725355120594966818839428.6512.9418.0824.08

1502586159073879238615430934057241245409.1313.7019.1825.57

1602724087564094751865741273147663651389.6214.4620.2827.06

17028620160443102651260516122380860573710.1115.2221.3728.56

18029999445245257783863619513285084633510.5915.9822.4730.05

19031378730147412916366722904189308693311.0816.7423.5631.54

20032758014949568048969826295093532753111.5717.5024.6633.03

21034137299851723181472929685897756812912.0618.2725.7534.52

220355165846538783140760330767101980872812.5419.0326.8536.01

230368958694560334466791364676106204932613.0319.7927.9537.51

240382751543581885791822398585110428992413.5220.5529.0439.00

250396544391603437117853432494114653052214.0021.3130.1440.49

260410337239624988443884466403118877112014.4922.0731.2341.98

270424130088646539768915500312123101171814.9822.8332.3343.47

280437922936668091094946534221127325231715.4723.5933.4344.96

290451715785689642419977568129131549291515.9524.3534.5246.46

3004655086337111937451008602038135773351316.4425.1235.6247.95

3104793014817327450711039635947139997411116.9325.8836.7149.44

3204930943307542963961070669856144221470917.4126.6437.8150.93

3305068871787758477221101703765148445530817.9027.4038.9152.42

Sheet1

0000

0000

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0000

0000

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0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

Sheet2

182823463127417052201167511222

RFCSSChildrenDriversAudult-PassTotalRFCSSChildrenDriversAdult-Pass

CUCUCUCUCU

199011000101

199144000404

199233000303

1993145001405

199457120057012

19953515131365014

1996619723406197234

199742611654150742721557

1998413121012271542511242

19991210162413223266035

200034421187076215

20010000000

Sheet2

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

Sheet4

0

0

0

0

0

0

0

0

0

0

0

0

Sheet3

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

B0.5

00

0.375-270

0.625-270

10

1.8600

5600

C500

00

1-500

1.5-500

2.50

3.7600

5600

0

0

0

0

0

0

Fishhook #1

0

0

0

0

0

0

Fishhook#2

J-TurnFishhook1Fishhook2

No BrakePulse BrakeRight to LeftLeft to RightRight to LeftLeft to Right

SSFRightLeftRightLeft

Explorer1.07oversteeroversteeroversteer*debead

Ranger1.08oversteerdebead

E150 Club Wagon1.11

Astro1.13

Tahoe1.13

Tracker1.14oversteeroversteer

Chevrolet S-101.16oversteeroversteer

Chevrolet C15001.23

Caravan1.26

Metro1.28oversteeroversteeroversteerundersteeroversteeroversteeroversteeroversteer

Lumina1.37oversteeroversteerdebeadn/aundersteerundersteer

Neon1.44Achieved Max Speed

* ABS Failure

Two Wheel Liftminor

moderate

major

Limit Condition

no limit condition or wheel lift for test conditions

bb

Sheet1

1808

1526

Width0.40.50.60.70.40.50.60.747008

1402448230593663725355120594966818839428.6512.9418.0824.08

1502586159073879238615430934057241245409.1313.7019.1825.57

1602724087564094751865741273147663651389.6214.4620.2827.06

17028620160443102651260516122380860573710.1115.2221.3728.56

18029999445245257783863619513285084633510.5915.9822.4730.05

19031378730147412916366722904189308693311.0816.7423.5631.54

20032758014949568048969826295093532753111.5717.5024.6633.03

21034137299851723181472929685897756812912.0618.2725.7534.52

220355165846538783140760330767101980872812.5419.0326.8536.01

230368958694560334466791364676106204932613.0319.7927.9537.51

240382751543581885791822398585110428992413.5220.5529.0439.00

250396544391603437117853432494114653052214.0021.3130.1440.49

260410337239624988443884466403118877112014.4922.0731.2341.98

270424130088646539768915500312123101171814.9822.8332.3343.47

280437922936668091094946534221127325231715.4723.5933.4344.96

290451715785689642419977568129131549291515.9524.3534.5246.46

3004655086337111937451008602038135773351316.4425.1235.6247.95

3104793014817327450711039635947139997411116.9325.8836.7149.44

3204930943307542963961070669856144221470917.4126.6437.8150.93

3305068871787758477221101703765148445530817.9027.4038.9152.42

Sheet1

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0000

0000

0000

0000

0000

0000

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Sheet2

182823463127417052201167511222

RFCSSChildrenDriversAudult-PassTotalRFCSSChildrenDriversAdult-Pass

CUCUCUCUCU

199011000101

199144000404

199233000303

1993145001405

199457120057012

19953515131365014

1996619723406197234

199742611654150742721557

1998413121012271542511242

19991210162413223266035

200034421187076215

20010000000

Sheet2

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

Sheet4

0

0

0

0

0

0

0

0

0

0

0

0

Sheet3

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

0000

B0.5

00

0.375-270

0.625-270

10

1.8600

5600

C500

00

1-500

1.5-500

2.50

3.7600

5600

Fishhook #1

Fishhook#2

J-TurnFishhook1Fishhook2

No BrakePulse BrakeRight to LeftLeft to RightRight to LeftLeft to Right

SSFRightLeftRightLeft

Explorer1.07oversteeroversteeroversteer*debead

Ranger1.08oversteerdebead

E150 Club Wagon1.11

Astro1.13

Tahoe1.13

Tracker1.14oversteeroversteer

Chevrolet S-101.16oversteeroversteer

Chevrolet C15001.23

Caravan1.26

Metro1.28oversteeroversteeroversteerundersteeroversteeroversteeroversteeroversteer

Lumina1.37oversteeroversteerdebeadn/aundersteerundersteer

Neon1.44Achieved Max Speed

* ABS Failure

Two Wheel Liftminor

moderate

major

Limit Condition

no limit condition or wheel lift for test conditions

bb

Star Rating Intervals - Summary (Linear) Approach

CG

22.41379310346.8965517241

20.31256.25

17.80821917815.4794520548

16.77419354845.1612903226

Narrow

Wide

Narrow

Wide

Narrow

Wide

Narrow

Wide

To move from 1 star to 2 stars

To move from 2 star to 3 stars

To move from 3 star to 4 stars

To move from 4 star to 5 stars

Stars

CG Height

oldstars

0.4541.04

0.41.12

0.31.24

0.21.45

0.11.55

0.071

0

1.450.5

1.45

0.1

1.450.1

1

0

1.240.5

1.24

0.2

1.240.2

1

0

1.120.5

1.12

0.3

1.120.3

1

0

1.040.5

1.04

0.4

1.040.4

1

Static Stability Factor

Probability of Rollover per Single Vehicle Crash

newstars

0.411.05

0.361.16

0.281.28

0.21.46

0.121.55

0.087

0

0.5

0.12

0.12

0.2

0.2

0

0.5

0

0.5

0.28

0.28

0.36

0.36

0

0.5

12%

28%

36%

Static Stability Factor

Probability of Rollover per Single Vehicle Crash

Sheet1

0.50.8

686052

32.428.624.87.6

10.410.286504796910.45429.325.922.46.9

1.050.360.26914634871.040.426.623.420.36.3

1.160.280.23457028811.120.323.320.517.85.5

1.280.20.2018965181.240.221.919.416.85.2

1.460.120.16121764411.450.1

1.550.0870.14406365911.550.071

1.4601.450

1.460.51.450.50.45380.0760.37780.530.7128301887

0.410.0930.3170.530.5981132075

1.460.121.450.11.1917981073

0.99740.1210.1

1.280.2

10.21.240

1.240.5

1.2801.240.2SS(w/2)/h

1.280.510.2

1.1601.120

1.160.51.120.5

1.16080.281.120.3

10.2810.3

1.04740.361.040

0.98420.361.040.5

1.0501.040.4

1.050.510.4

Measure of Rollover RiskRollovers per Single Vehicle Crash (ro/svc) single veh. ro/ 10k register vehicles = (# c/10k rv) X (svc/# c) X (ro/svc) # c/10k rv: driven by driver/road effects svc/# c: influenced by driver/road; also will show effect of ESC ro/svc; least sensitive to driver/road effectsBetter to consider factors separately

Rewarding ESCA Problem for SSFWhat is ESC?Treatment in consumer info web-siteExpected to reduce (svc/total crashes)Expected to reduce untripped rolloverToo new for much statistical evidenceNHTSA monitoring ESC effectiveness

Monitoring ESC Effectiveness1996-7 Cadillac Seville, Deville, Eldorado1996-9 data from 9 statesNote: very scant data for Lexus LS 400 and M-B ML320 is more encouraging

Dynamic Maneuver TestingTwo Main TypesPath following Double Lane ChangePlus Face ValidityMinus Objectivity and RepeatabilityDefined Steering- FishhookPlus Objectivity and repeatabilityMinus Less Face ValidityInformation added by maneuver testsRoll momentum effect at steering reversalOperation of ESC

Path Following TestDouble Lane Change

Comparison of Double Lane Change Steer Input for Two Drivers

Defined Steering of Fishhook Maneuver

Close to full lockApprox. 270 degrees

Defined Steering Test - Fish Hook Vehicle 2 PathVehicle 1 Path

Difficulties Common to All Driving Maneuver Tests Driver safetyHigh costEffect of outriggersEffect of tire wearComplexity of ratingsCorrelation to crash statistics unlikelyEffect of pavement friction variationMay be overwhelmed by the brake intervention aspect of ESC- good or bad?

How Best to Reward ESC?Yaw StabilityOriginal purpose of ESCCannot be duplicated by driver actionMay not be rewarded by maneuver testsFuture data needed to know effectiveness Brake Intervention Not different from driver inputBiggest vehicle attribute in maneuver test?Future data needed to know effectiveness Treatment of ESC requires wisdom