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5、perational Definitions of Driving Performance Measures and Statistics RATIONALE A common and consistently defined vocabulary is a basic requirement for comparing evaluation procedures and their results for driving contexts, vehicles, and vehicle components. This is the reason for foundational docume
6、nts such as SAE J1100 Motor Vehicle Dimensions (Society of Automotive Engineers, 2009) and related mobility documents (Steinfeld, Fong, Kaber, Lewis, Scholtz, and Goodrich, 2006). (See also National Research Council, 2011.) As shown by Savino (2009) and Green (2012), many terms used to describe driv
7、ing performance are not consistently named, defined (if they are defined at all), or used in the automotive engineering and research literature. This inconsistency makes comparing studies, test procedures, and results difficult, which in turn can compromise safety and usability. To overcome the inco
8、nsistency problem, this document provides standard names and definitions of driving performance measures and statistics, as well as supporting information to encourage their use. TABLE OF CONTENTS 1. SCOPE . 6 1.1 Applicable Vehicles 6 1.2 Applicable Contexts . 6 1.3 Purpose 6 2. REFERENCES . 7 2.1
9、Applicable Publications 7 2.1.1 SAE Publications 7 2.1.2 Related Publications 7 3. CITING J2944 DEFINITIONS 7 4. INTRODUCTION 8 4.1 Background and Current Practice 8 4.2 Approach 9 5. GENERAL MEASUREMENT AND REPORTING GUIDANCE AND REQUIREMENTS . 9 5.1 Good Measurement Practice . 10 5.1.1 Specify a w
10、ell-defined start point . 10 5.1.2 Specify a well-defined end point 10 5.1.3 Measure driver control movements accurately and precisely 11 5.1.4 Eliminate sensor noise . 12 5.1.5 Eliminate sensor and sensor integration lags 12 5.1.6 Separate vehicle automated actions from driver actions . 13 5.1.7 Ex
11、clude preparatory movements from the accelerator or brake as well as random movements 13 5.2 Good Reporting Practice 14 5.2.1 Identify when drivers have both hands off of the steering device 14 5.2.2 Identify when drivers use both feet to drive . 14 5.2.3 Match the roadway segments for conditions be
12、ing compared. 15 5.2.4 Make the sample durations equal 16 5.2.5 Adjust for extreme responses 16 SAE INTERNATIONAL J2944 Issued JUN2015 Page 2 of 171 5.2.6 Percentiles are sometimes the most revealing statistic . 17 5.2.7 Report distribution parameters to aid modeling . 17 5.2.8 Select response measu
13、res and statistics appropriate for the question(s) posed 17 5.3 Summary of General Measurement and Reporting Requirements . 17 6. GENERAL DEFINITIONS 18 6.1 Vehicle Reference Surfaces 18 6.1.1 Leading surface 18 6.1.2 Trailing surface . 18 6.1.3 Surfaces beyond vehicle bumpers . 18 6.2 Trafficway El
14、ements . 19 6.2.1 Trafficway . 19 6.2.2 Traveled way 20 6.2.3 Parking lane . 23 6.2.4 Bicycle lane 23 6.2.5 Roadway 24 6.2.6 Paved roadway 26 6.2.7 Shoulder . 26 6.2.8 Usable shoulder . 27 6.2.9 Vehicle Lane 27 6.3 Trafficway Element Boundaries . 27 6.3.1 Roadway boundary 28 6.3.2 Lane boundary . 28
15、 6.3.3 Lane expansion 28 6.4 Terms Relating to Data Types . 29 6.4.1 Measure . 29 6.4.2 Measurement . 29 6.4.3 Statistic . 29 6.5 General Terms for Driver Reactions to Events and Movements . 29 6.5.1 Event 29 6.5.2 Reaction time (RT) . 30 6.5.3 Movement time (MT) 30 6.5.4 Response time (RspT) . 31 6
16、.5.5 Types of movement response end points 31 6.5.6 Perception-response time (PRT) . 32 7. LONGITUDINAL CONTROL: OPERATIONAL DEFINITIONS FOR DRIVERS PEDAL RESPONSES . 35 7.1 Response Time Classification Scheme . 35 7.1.1 Scheme overview . 35 7.1.2 The 1/5/75 rule to identity response movement start
17、or end point 37 7.1.3 Final movement is maximum response of each driver 38 7.2 Response Time Measures . 38 7.2.1 Response time until accelerator moved . 38 7.2.2 Response time until brake moved 38 7.2.3 Response time until foot first moved 38 7.2.4 Response time until accelerator completely released
18、 . 38 7.2.5 Response time until brake completely released 39 7.2.6 Response time until accelerator contacted 39 7.2.7 Response time until brake contacted . 40 7.2.8 Response time until brake lights on . 41 7.2.9 Response time until brake lights off . 41 7.2.10 Response time until 75 % accelerator va
19、lue 41 7.2.11 Response time until 75 % brake value. 41 7.2.12 Response time until maximum jerk while accelerating 42 7.2.13 Response time until maximum jerk while braking 42 7.2.14 Response time until maximum accelerator value 43 7.2.15 Response time until maximum brake value . 43 7.3 Guidance for U
20、se of Accelerator Pedal and Brake Pedal Measures . 44 8. LONGITUDINAL CONTROL: OPERATIONAL DEFINITIONS OF VEHICLE-BASED MEASURES . 44 SAE INTERNATIONAL J2944 Issued JUN2015 Page 3 of 171 8.1 Vehicle Longitudinal State Measures . 44 8.1.1 Distance gap 44 8.1.2 Time gap 48 8.1.3 Distance headway 50 8.
21、1.4 Time headway 51 8.1.5 Center of gravity (CG) distance separation 51 8.1.6 Center of gravity (CG) time separation 52 8.1.7 Spatial center (SC) distance separation 52 8.1.8 Spatial center (SC) time separation . 52 8.1.9 Range . 52 8.1.10 Guidance for longitudinal state measures 53 8.2 Vehicle Long
22、itudinal Exposure Statistics . 54 8.2.1 Time to collision (TTC) . 54 8.2.2 Minimum time to collision (Minimum TTC, TTCmin) 56 8.2.3 Minimum adjusted time to collision (Adjusted TTC) . 57 8.2.4 Time exposed time to collision (TETTC) 58 8.2.5 Time integrated time to collision (TITTC) . 58 8.2.6 Invers
23、e time to collision 59 8.2.7 Required deceleration 60 8.3 Vehicle Following Measures 64 8.3.1 Coherence (2(f) 64 8.3.2 Gain 66 8.3.3 Phase angle . 67 8.3.4 Time delay 67 8.3.5 Quality of vehicle following, correlation coefficient based on cross-correlation . 72 8.3.6 Guidance for vehicle following m
24、easures 72 9. LATERAL CONTROL: OPERATIONAL DEFINITIONS FOR DRIVER STEERING RESPONSES TO EVENTS . 73 9.1 Steering Performance Measures . 73 9.1.1 Steering reaction time 73 9.1.2 Steering movement time 75 9.1.3 Steering response time 75 9.1.4 Guidance for steering performance measures 76 9.2 Steering
25、Performance Statistics . 77 9.2.1 Steering reversal (SR) 77 9.2.2 Number of steering reversals . 84 9.2.3 Steering reversal rate (SRR) 84 9.2.4 Steering entropy (HP) . 84 10. LATERAL CONTROL: OPERATIONAL DEFINITIONS OF VEHICLE-BASED MEASUREMENTS . 85 10.1 Lateral Position Measures and Statistics . 8
26、5 10.1.1 Lateral lane position . 85 10.1.2 Mean lateral lane position 89 10.1.3 Standard deviation of lane position (SDLP) . 90 10.2 Lane Departure Measures and Statistics . 90 10.2.1 Lane Departure 90 10.2.2 Number of lane departures 96 10.2.3 Lane departure duration . 97 10.2.4 Lane departure magn
27、itude . 97 10.3 Lateral Position Exposure Statistics . 98 10.3.1 Time-integrated lane departure magnitude 98 10.3.2 Time to line crossing (TLC) 99 10.3.3 Minimum time-to-line crossing (TLCmin) . 102 10.3.4 Mean time-to-line crossing (Mean TLCmin) . 103 10.3.5 Inverse time to line crossing 104 10.4 L
28、ane Change Measures and Statistics 104 10.4.1 Lane change 104 10.4.2 Number of lane changes 110 10.4.3 Lane change duration 111 SAE INTERNATIONAL J2944 Issued JUN2015 Page 4 of 171 10.4.4 Lane change severity . 113 10.4.5 Lane change urgency. 113 10.5 Roadway Departure Measures and Statistics 114 10
29、.5.1 Roadway departure 114 10.5.2 Number of roadway departures . 115 10.5.3 Roadway departure duration 115 10.5.4 Magnitude of roadway departure . 115 10.5.5 Roadway pavement departure . 116 10.5.6 Time integrated roadway departure magnitude . 116 11. NOTES . 116 11.1 Marginal Indicia 116 APPENDIX A
30、 CALCULATION OF TIME TO COLLISION (TTC) . 117 APPENDIX B CALCULATION OF MINIMUM TIME TO COLLISION (TTCMIN) 121 APPENDIX C CALCULATION OF MINIMUM ADJUSTED TIME TO COLLISION 123 APPENDIX D CALCULATION OF TIME EXPOSED TIME TO COLLISION (TETTC OR TET) 126 APPENDIX E CALCULATION OF TIME INTEGRATED TIME-T
31、O-COLLISION (TITTC OR TIT) . 129 APPENDIX F CALCULATION OF STEERING WHEEL REVERSALS 131 APPENDIX G CALCULATION OF STEERING ENTROPY 137 APPENDIX H CALCULATION OF TIME TO LINE CROSSING, TRIGONOMETRIC METHOD . 145 APPENDIX I CALCULATION OF MINIMUM TIME TO LINE CROSSING - APPROXIMATE METHOD FOR FIELD DA
32、TA 148 Figure 1 Using both feet to drive 15 Figure 2 Two-foot braking 15 Figure 3 Truck with a ladder that adds a trailing surface to its length 18 FIgure 4 Trafficway, traveled way, and roadway 19 Figure 5 Traveled way, roadway, and usable shoulder . 21 Figure 6 Example of visually contiguous paved
33、 traveled way, a paved shoulder, and a partially usable unpaved shoulder . 22 Figure 7 Example of a U.S. urban traveled way with a contiguous gutter and curb . 22 Figure 8 Illustration of vertical drop off . 23 Figure 9 Parking lanes . 23 Figure 10 Bicycle lanes separated by a barrier (left panel) a
34、nd not separated (right panel) from the traveled way 24 Figure 11 Perception-response time distribution for 321 drivers . 33 Figure 12 Normal probability plot for perception time (top row) and PRT (bottom row) for younger and older drivers 34 Figure 13 Example of brake application and release . 39 F
35、igure 14 Longitudinal distance or time measures 45 Figure 15 Gap alternatives in a multi-lane traveled way 45 Figure 16 Merging onto a multi-lane traveled way . 46 Figure 17 Passing maneuver on a two-lane traveled way . 46 Figure 18 Gaps when proceeding from stop to cross a right-angle intersection
36、47 Figure 19 Gaps when proceeding from stop to cross an angled intersection 47 Figure 20 Gap for left turn across path 47 Figure 21 Time gap distribution 49 Figure 22 Gap versus range . 52 Figure 23 Distribution of TTC from 0 - 10 seconds 55 Figure 24 Hypothetical tradeoff between gap and TTC includ
37、ing areas of indifference . 56 Figure 25 Minimum time to collision . 57 Figure 26 Inverse TTC versus speed of subject vehicle in hard braking scenario 60 Figure 27 Three cases of required deceleration 61 Figure 28 Last-second braking data from CAMP . 63 Figure 29 Sample speed trace of subject vehicl
38、e, y(t), following the lead vehicle, x(t) . 65 Figure 30 Illustration of cross-correlation measurement (top) and sample plot (bottom) . 69 Figure 31 Cross-correlation between subject and lead vehicles 70 Figure 32 Peak of cross-correlation function (offset of -149 samples) . 71 Figure 33 Steering re
39、action, movement, and response times 74 Figure 34 Driver response to lane departure (LDW) and lane change merge (LCM) warnings . 76 SAE INTERNATIONAL J2944 Issued JUN2015 Page 5 of 171 Figure 35 Median lateral position following LDW alerts from the RDCW field test 77 Figure 36 Illustration of steeri
40、ng reversals . 78 Figure 37 Steering pattern for a large truck for straight-line driving . 79 Figure 38 Effect of the reversal threshold on task reliability (correlation of two successive test runs) . 80 Figure 39 Performance effect size as a function of steering wheel gap (amplitude) size using a 2
41、 Hz filter cutoff frequency 82 Figure 40 Finding a steering reversal using a velocity dead band . 83 Figure 41 Example of lane position showing curve cutting 86 Figure 42 Example of lateral position relative to lane edge (option c) relative to the front axle (option 2) . 87 Figure 43 Chord lane boun
42、dary problem . 88 Figure 44 Cubic spline approximation of a sine wave 88 Figure 45 Distribution of lateral positions from the IVBSS project for all driving conditions . 89 Figure 46 Lane departure, option A: Widest part of vehicle crosses lane marking centerline . 92 Figure 47 Lane departure, option
43、 B: Front tire touches inside of lane marking 93 Figure 48 Lane departure, option C: Front tire touches outside of lane marking . 93 Figure 49 Lane departure, option D: Front tire outside of lane marking . 94 Figure 50 Lane departure, options E and F: Any tire touches inside/outside of lane marking
44、94 Figure 51 Distribution of lane departure durations . 97 Figure 52 Maximum lane departure magnitude (incursion) . 98 Figure 53 Time-integrated lane departure magnitude 98 Figure 54 TLC versus time left and right lane boundary line . 103 Figure 55 Gaze time course during a lane change averaged acro
45、ss subjects 106 Figure 56 Mean gaze durations associated with lane changes . 106 Figure 57 Mean time histories of various lane change measures and statistics 108 Figure 58 Number of lanes changes per 100 miles . 111 Figure 59 Distribution of lane change durations . 112 Figure A1 TTC situation at t =
46、 T for two approaching vehicles . 117 Figure A2 TTC situation at t = T for a perpendicular approach 118 Figure A3 Types of potential collisions for an acute angle of approach . 119 Figure C1 Normal probability plots for TTCmin, relative velocity at collision, and adjusted TTCmin for assumed decelera
47、tions of 0.4 G (top row) and 0.75 G (bottom row) 125 Figure D1 Example time-to-collision profile of a driver-vehicle combination in motorway traffic . 126 Figure F1 Example of steering wheel reversals. 131 Figure F2 Illustration of the method for finding stationary points of the steering wheel angle
48、 signal. 132 Figure G1 Computation of steering angle error 138 Figure G2 Frequency distribution of e(n) used to determine . 138 Figure G3 Binning the frequency distribution of e(n) 139 Figure G4 Change in frequency distribution of e(n) with workload . 140 Figure G5 Comparison of AR and Taylor high-p
49、ass filters . 141 Figure H1 Straight road TLC parameters for determining the length of the arc DLC . 146 Figure H2 Curved road TLC parameters 147 Figure I1 TLC waveforms and identification of TLC minimum values . 149 Table 1 Response time measures classification scheme . 36 Table 2 “Average spacing” (distance gap) between vehicles for highways 48 Table 3 Quantities related to required deceleration 62 Table 4 Variable definitions for requir
