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4、6-0790Email: custsvcsae.orgSAE WEB ADDRESS: http:/www.sae.orgSURFACEVEHICLEINFORMATIONREPORTJ2400ISSUEDAUG2003Issued 2003-08Human Factors in Forward Collision Warning Systems: Operating Characteristics and User Interface RequirementsForewordThis document serves as the final committee and stakeholder
5、s draft of SAE J2400 Human Factors inForward Collision Warning Systems: Operating Characteristics and User Interface Requirements.We note that for the sake of uniformity and international harmonization, it would be desirable for this document tobe consistent with a related draft ISO standard (“Road
6、vehicles Forward Vehicle Collision Warning System Performance requirements and tests procedures” ISO/TC 204/WG 14 N144.1). However, please note thatdifferences exist between these two drafts. In part this is due to a difference in emphasis, with the ISO givingrelatively more attention to details of
7、system sensor capabilities and algorithms, and SAE J2400 putting moreemphasis on the alert zone parameters and human factors considerations of the operator interface requirements.There is also a major distinction in scope, as SAE J2400 deals solely with a single-stage alert or the last stage of amul
8、ti-stage alert (sometimes referred to as an “imminent collision warning”), whereas ISO distinguishes twocategories of warning “preliminary collision warning” (i.e., non-imminent) and “collision warning” (i.e., imminent).Readers should also note that this is an “information report”, not a recommended
9、 practice or standard. Due to thelack of operational data, this first information report should be used as a starting point or reference for designers offorward collision warning systems. The authors attempted to support each of the design recommendations withsupporting references. Future FCW recomm
10、ended practices or standards will be based on operational data tobolster recommendations and requirements.TABLE OF CONTENTSPREFACE. 31.0 SCOPE. 42.0 REFERENCES. 43.0 DEFINITIONS. 54.0 OPERATING CHARACTERISTICS 75.0 PERFORMANCE EVALUATION TEST METHODS . 166.0 APPENDIX . 33SAE J2400 Issued AUG2003-2-1
11、. ScopeForward Collision Warning (FCW) systems are onboard systems intended to provide alerts to assistdrivers in avoiding striking the rear end of another moving or stationary motorized vehicle. This SAEInformation Report describes elements for a FCW operator interface, as well as requirements and
12、testmethods for systems capable of warning drivers of rear-end collisions.This information report applies to original equipment and aftermarket FCW systems for passenger vehiclesincluding cars, light trucks, and vans. This report does not apply to heavy trucks. Furthermore, this documentdoes not add
13、ress integration issues associated with adaptive cruise control (ACC), and consequently, aspectsof the document could be inappropriate for an ACC system integrated with a FCW system.2. References2.1 Applicable PublicationsThe following publications form a part of the specification to the extent spec
14、ifiedherein. Unless otherwise indicated the latest revision of SAE publications shall apply.2.1.1 OTHER PUBLICATIONSAmerican Association of State Highway and Transportation Officials AASHTO(2001), A policy ongeometric design of highways and streets.Balbale and R. Kiefer (2001). Driver preference ran
15、kings of various collision avoidance related symbol.Presented at ISO TC22/SC13/WG5 (Road Vehicles-Symbols for Controls, Indicators and Telltales)meeting in Dresden, Germany.Gilbert, R.K., Zoratti, R., Becker, G., Brumbaugh, T., Chaplin, M., Harrison, M., and K. Gondoly (1997).Characterization and ev
16、aluation of a prototype forward-looking automotive radar: Final Report. Officeof Crash Avoidance Research, National Highway Transportation Safety Administration. Washington,DC. Report No. 654100-9-F.ISO TC 204/WG14/N144.1. Road vehicles Forward Vehicle Collision Warning System Performancerequirement
17、s and test procedures. Draft only, 1999-07-19Kiefer, R., LeBlanc, D., Palmer, M., Salinger, J., Deering, R., and M. Shulman (1999). Development andvalidation of functional definitions and evaluation procedures for collision warning/avoidance systems.DOT HS 808 964. Office of Crash Avoidance Research
18、, National Highway Transportation SafetyAdministration. Washington, DC.LeBlanc, D., Kiefer, R., Deering, R., Shulman, M., Palmer, M,. and Salinger, J. (2001). Forward collisionwarning: preliminary requirements for crash alert timing. Society of Automotive Engineers #2001-01-0462.Scolnik, M. (1970).
19、Radar Handbook. McGraw Hill.U.S. Department of Transportation, Federal Highway Administration (2001). Manual on Uniform TrafficControl Devices (MUTCD).3. DefinitionsFor the purpose of this information report (IR), the following definitions apply. Some of thesedefinitions have been adopted from ISO/T
20、C204/WG14/N144, and others are specific to this SAE IR.3.1 Forward Collision Warning (FCW) SystemsSystems intended to provide alerts to assist drivers in avoidingstriking the rear-end of another moving or stationary vehicle, and to help mitigate the impact of rear-endcrashes.3.2 Active ModeFCW syste
21、m is receiving power and is monitoring the area ahead to detect hazards.3.3 Actual Deceleration Parameter (ADP)The assumed deceleration of the host vehicle (expressed in gs) inresponse to an alert, used in computing the latest allowable FCW alert onset for a given kinematic situation.3.4 Alert ZoneT
22、he alert zone defines which vehicles in front of the subject vehicle are allowed to trigger FCWalerts. For an alert to be allowed, some portion of the target vehicle must lie within the alert zone at the onset ofthe alert, or be predicted to be within the alert zone at a time after the onset of the
23、alert.SAE J2400 Issued AUG2003-3-3.5 aLVActual acceleration (neg. for braking) of the LV at the onset of an observed FCW alert.3.6 aSVActual acceleration (negative for braking) of the subject vehicle at the onset of an observed FCW alert.3.7 Brake System LagTime interval between when the brake pedal
24、 is pressed and the vehicle begins todecelerate.3.8 Time GapThe time require (at current speeds) for the front bumper of the host vehicle to reach the currentposition of the rear bumper of the lead vehicle.3.9 Host VehicleThe FCW-equipped vehicle under consideration (also called subject vehicle).3.1
25、0 Imminent Collision WarningA warning to be given to the SV driver in situations which potentially require animmediate corrective action by the driver.3.11 Kinematic SituationA particular scenario involving a subject vehicle and lead vehicle, specifying values fortheir speeds, accelerations, and lat
26、eral and longitudinal placements at a given instant.3.12 Lead Vehicle (LV)A vehicle in the path of the subject vehicle which presents a potential threat of collision(also has been referred as the principal other vehicle).3.13 Non-functioningThe status of a FCW system that has been manually turned of
27、f by the driver.3.14 Required Deceleration Parameter (RDP)The assumed deceleration of the host vehicle (expressed in gs)in response to an alert, used in computing both the recommended timing of an FCW alert onset and theearliest allowable FCW alert onset for a given kinematic situation.3.15 Standby
28、ModeThe system is receiving power, but the sensors and FCW system is not activated.3.16 Subject Vehicle (SV)The FCW-equipped vehicle under consideration (same as “host vehicle”).3.17 Telltale Visual DisplayA visual display which appears when and only when the underlying condition itsignals is in eff
29、ect. (For example, a “low fuel” icon.)3.18 Total Delay Time (DT)The assumed time interval between onset of a crash alert and the start ofdeceleration, comprising the drivers reaction time, and the nominal brake system lag.3.19 VSVActual speed of the subject vehicle at the onset of the FCW alert.3.20
30、 VLVActual speed of the lead vehicle at the onset of the FCW alert.4. Operating Characteristics4.1 System and Information Display Characteristics4.1.1 APPLICATION OF POWERThe vehicle shall apply power to the FCW system at engine start-up.4.1.2 ACTIVATION FOR USEFCW systems should be automatically sh
31、ifted from the standby mode to the activemode for hazard detection when the vehicle is in forward motion above the minimum operating speed (see4.1.3).4.1.3 MINIMUM OPERATING SPEEDThe minimum speed at which the system is active for use should be no greaterthan 40 kph. Manufacturers may activate their
32、 systems at lower speeds.SAE J2400 Issued AUG2003-4-4.1.4 MAXIMUM OPERATING SPEEDThere is no upper speed limit. The FCW system should provide an indicationto the driver if its performance is limited at higher speeds.4.1.5 NON-FUNCTIONING OR SYSTEM LIMITATION INDICATIONDrivers shall be informed by a
33、continuous display thatthe system is non-functioning or is in a system limitation mode. A brief tone should accompany the onset ofthe failure or system limitation. System limitation conditions may include high subject vehicle speeds,obstructed or blinded sensor(s), and/or severe weather conditions.4
34、.1.6 BUILT-IN DIAGNOSTIC TESTINGAll FCW devices shall include built-in diagnostic testing to verify that thedevice is capable of operating within specified performance limits. Diagnostic testing shall be performedautomatically each time the ignition switch is turned on. Devices that fail shall autom
35、atically shift into a non-functioning mode and alert the driver (see 4.1.4).4.1.7 AUTOMATIC TERMINATION OF WARNINGSThe device that triggers a warning should terminate the warningautomatically once the riggering condition no longer exists or appropriate driver response (e.g., a given levelof braking)
36、 is initiated.4.1.8 AUDITORY DISPLAYSThe auditory display for imminent crash warnings shall be a distinctive, non-speechacoustic warning. The sound should be perceived by the driver to emanate from the general direction ofthreat (i.e., from the front of the vehicle). The alert sound tentatively reco
37、mmended from Kiefer et al. (1999;pg 4-28) based on closed-course testing is a starting point (which was played out of both front speakers), butfurther field operational testing (incorporating real-world nuisance and false alarm types and rates) will beneeded to assess driver acceptance of this sound
38、.4.1.9 DEFAULT WARNING INTENSITYThe warning should not startle. It is difficult to provide a recommendedpractice in this area. On one hand, warnings need to be heard over ambient noise (e.g., if the car windowsare rolled down). On the other hand, startling drivers is not acceptable. A starting point
39、 based on the Kiefer etal. (1999) data for the warning intensity should be 75 dBA. Adjusting the sound level based on the ambientsound level should be considered. However, driver acceptance of such a strategy should be evaluated.4.1.10 ONSET AND OFFSET RATESThe onset rate for sounds or tones used in
40、 crash avoidance warnings should berapid enough to alert the driver but not so rapid as to induce severe startle effects. Onset rates of greaterthan 1 dB/msec but less than 10 dB/msec should be used.4.1.11 WARNING DURATIONThe device that triggers a warning should terminate the warning automatically
41、oncethe triggering condition no longer exists. Based on driver response to the situation, other automatic andmanual methods for terminating warnings may be permissible.4.1.12 INTERRUPTION OF OTHER AUDITORY DISPLAYSImminent collision avoidance warnings should automaticallyinterrupt or decrease the vo
42、lume of other inputs to all speakers when warnings are displayed.4.1.13 VISUAL, AUDITORY, AND HAPTIC WARNINGSVisual displays shall not be used for stand-alone imminentcollision warnings. Such warnings should be multi-modal. Currently, there are many unresolved issuesassociated with the implementatio
43、n and driver behavior issues surrounding haptic alerts. Consequently, atpresent, a dual-modality alert is recommended which includes both a visual and auditory display.4.1.14 VISUAL DISPLAY LOCATIONVisual warnings shall be located within a 10-degree cone of the drivers line ofsight. Qualitatively, t
44、his generally implies a top-of-dashboard or head-up display location. A conventionaldashboard location shall not be used for the visual warning. The rationale for this is based on the possibilitythat an instrument panel-based visual warning may distract the driver from the hazard ahead.SAE J2400 Iss
45、ued AUG2003-5-4.1.15 MANUAL ADJUSTMENT OF VISUAL DISPLAY INTENSITYIf the visual display is in the from of a telltale, intensityshould not be adjustable. However, if the visual display is not a telltale, the vehicles display brightnessadjustment should be restricted such that at the dimmest setting t
46、he FCW status display remains visible andthe driver can readily perceive the warning displays.4.1.16 CHARACTERISTICS OF THE VISUAL CRASH ICONCollision warning systems should use red. The symbol usedshould be the Kiefer et al. (1999) symbol (shown on the left below) or the more recent symbol develope
47、d byBalbale and Kiefer (2001) for ISO consideration (shown on the right below). The latter symbol has theadvantage of being developed as part of an effort for an integrated set of visual crash avoidance-relatedwarnings for various crash avoidance relates systems. For each of these symbols, the symbo
48、l should beblack and the background red. For specific characteristics of these icons see Kiefer et al. (1999) and Balbaleand Kiefer (2001).4.2 Requirements for the Occurrence of Crash AlertsThe following sections are based largely on Kiefer et al.(1999) and LeBlanc et al. (2001). These requirements
49、are considered preliminary and are likely to be revisedbased on ongoing research and experience.4.2.1 GEOMETRIC CHARACTERISTICS OF THE ALERT ZONEAn alert zone defines which vehicles in the subjectvehicles path are allowed to trigger FCW imminent alerts. For an alert to be allowed, some portion of thetarget vehicle must lie within the alert zone at the onset of the alert, or be predicted to be within the alert zoneat a time 1.52 seconds after the alert onset. The minimum zone width is the width of the vehicle and themaximum z
