DEPARTMENT OF TRANSPORT FEDERAL OFFICE OF ROAD SAFETY DOCUMENT RETRIEVAL INFORMATION Report NO. mte Pagea ISBN ISSN CR60 June 1999 174 rl 642 51402X CR-0810-77C Title and Subtitle SPEED PERCEPTION 2: Drivers' judgmts of safety and sped on mal straight and curved roads and for different follwing distances. Author (5) FILDES, B.N., LEENING, A.C. and CORRIGAN, J.McM. performing Orqanisation Royal Automobile Club of Victoria (RACV) Limited, 550 Princes Highway, NOBLE PARK, VICTORIA, 3174, AUSTRALIA. ipon s or Federal Office of Road Safety, G.P.O. Sox 594, CANSCRRA, A.C.T., 2601, AUSTRALIA. rvailable from Price/Availability/FOmt 'ederal Office of Road Safety I lbstract This project was a continuation of a previous study in speed perception that evaluated the role of the type of road and road width, roadside development, travel speed, driving experience and the sex of the driver on estimates of safety and travel speed (Fildes, Fletcher & Corrigan, 1987). In the first experiment, the effect of night driving and time of testing on a driver's perception of speed on straight rural roads was assessed using the previous methodology. A validation study was performed to test whether the laboratory assessment technique was suitable for assessing speed perception at rural curves. A multi- factorial experiment followed that assessed the role of the previous road, environment, and driver variables (as well as curve radius and curve direction) on drivers' estimates of safety and travel speed on flat rural curves. The last experiment was a preliminary study to see whether the speed perception methodology was also suited to testing perceptions of following distance in rural areas. The final chapter reviewed the literature on road treatments that would be suitable for use as speed perception countermeasures. A number of treatments were identified and a progrme of research necessary to evaluate their effectiveness and potential road safety costs and benefits was outlined. Keyword 5 SPEED, PERCEPTION, HIGHWAY, CARRIAGEWAY, PAVEMENT, ENVIRONMENT, WOMAN, EXPERIENCE(HUMAN), RECENTLY QUALIFIED DRIVER, LABORATORY, SAFETY, RURAL AREA, RISK TAKING, HEADWAY, VEHICLE SPACING I NGTES -RS reports are diaserinated in the intereat of infonation exchange. (2) The vievs expressed are those of the author(.) and do not naceasarily represent those of the Comnwealth Government. (3) The Federal Office of Road Safety publishes two aeries of reports (a) report. generated as a result of research done within PORS are publiahed in the OR serles; (b) reports of research cmducted by other organisatioy on behalf of PORS are publlshed in the CR Serles. The authors are indebted to the Federal Office of Road Safety, Commonwealth Department of Transport and Communications, Australia, for their sponsorship, interest and assistance in this project. A study of this magnitude could not have been undertaken without the help and co-operation of a large number of RACV staff. In particular, Mr. Ian Russell of the Traffic & Safety Department assisted in setting up the project, the Chief Engineer, Mr. John McKenzie, provided the research vehicle, Mr. Don Finegan assisted with the necessary vehicle modifications and associated equipment, and many other staff willingly agreed to participate in the experiments. The authors are also indebted to Mr. Heinz Schulte and Mr. Don Wells of Hella Manufacturing Co. Pty. Ltd. who generously aided in the selection and supply of the Rallye 2000 spotlights used for night filming. The Victorian Police force also assisted in traffic control during the night filmCng sessions and we are grateful to Superintendent R. Stevens and his staff for their co- operation. Our thanks, too, to Major L. Morgan, Officer Comnding, EDE Proving Ground at Monegetta, Victoria and staff for assisting with site filming and testing. Monash University generously contributed in the preparation of the stimulus materials. In particular, Mr. Ken Hall, Mr. Vladimar Kohout and Mr. Richard Hobbs of the Department of Psychology supplied and fitted the Bolex camera to the research vehicle, while Mr. Don Hausser and Mr. John Torrance of the Higher Education Research Unit kindly helped with film editing. TABLE OF CONTENTS 1 . INTRODUCTION ............................................. 1 1.1 PROJECT OBJECTIVES ................................ 1 1.2 THE PREVIOUS PROJECT .............................. 2 1.3 ROAD ALIGNMENT .................................... 2 1.3.1 Horizontal Curves .......................... 3 1.3.2 Vertical Curvature ......................... 4 1.4 DAY AND NIGHT VISION .............................. 5 1.4.1 Time Of The Day Of Testing ................. 6 1.5 FOLLOWING DISTANCE ................................ 7 1.5.1 Recommended Following Distances ............8 1.5.2 Research Required .......................... 9 1.6 RESEARCH STRATEGY ................................. 9 1.6.1 Laboratory Experimentation .................9 1.6.2 Stimulus Presentations .................... 10 1.6.3 Free Vehicle Speed Data ................... 10 1.6.4 Independent Variables ..................... 10 1.6.5 Controlled Factors ........................ 11 2 . DAY AND NIGHT VISION EXPERIMENT ......................... 13 2.1 STIMULUS MATERIALS ............................... 13 2.2 APPARATUS ........................................ 17 2.3 EXPERIMENTAL PROCEDURE........................... 17 2.4 RESULTS .......................................... 20 2.4.1 Safe Operating Speed Responses ............21 2.4.2 Speed Estimation Errors ...................25 2.4.3 Free Speed Data ........................... 30 2.5 DISCUSSION ....................................... 32 2.5.1 Presentation Speed ........................ 32 2.5.2 Type of Road .............................. 33 2.5.3 Day and Night Driving ..................... 34 2.5.4 Roadside Environment ...................... 36 2.5.5 Driver Variables .......................... 37 2.5.6 Speed Behaviour and Perception ............ 38 3 . LABORATORY VAtIDATION STUDY ............................. 39 3.1 STIMULUS MATERIALS ............................... 39 3.1.1 Movie Film Sequences ...................... 42 3.1.2 Free Speed Measurement .................... 42 3.2 APPARATUS ........................................ 42 3.3 SUBJECTS ......................................... 43 3.4 EXPERIMENTAL PROCEDURE ........................... 43 3.4.1 Road Trials ............................... 43 3.4.2 Laboratory Experiment ..................... 44 3.5 RESULTS .......................................... 45 3.5.1 Safe Operating Speed Responses ............45 3.5.2 Speed Estimation Errors ...................47 3.5.3 Free Speed Data ........................... 49 3.5.4 Road & Environment Effects ................49 3.6 DISCUSSION ....................................... 53 4 . HORIZONTAL CmWATmzE EXPERfMENT ......................... 57 4.1 STIMULUS MATERIALS ............................... 57 4.2 EXPERIMENTAL PROCEDURE ........................... 61 4.3 RESULTS .......................................... 62 4.3.1 Safe Operating Speed Responses ............ 62 4.3.2 Speed Estimation Errors ................... 67 4.3.3 Free Speed Data ........................... 72 4.4 DISCUSSION .. ..................................15 4.4.1 Prese 3 ion Speed ......................... 15 4.4.2 Type oad ...............................16 4.4.3 Curve Ra ius and Roadside Environment ......18 4.4.4 Curve Direction ............................ 79 4.4.5 Driver Variables ........................... 80 5 . LABORATORY VALIDATION STUDY CLOSE FOLLOWIRG ............83 5.1 STIMULUS MATERIALS ................................- 83 5.2 ROAD TRIALS .......................................88 5.3 LABOPATORY TRIALS ................................. a9 5.4 RESULTS ........................................... 90 5.4.1 Safe Operating Distance Responses ..........90 5.4.2 Speed Estimation Errors ....................92 5.4.3 Free Speed Data ............................94 5.4.4 Other Variable Effects ..................... 94 5.5 DISCUSSION ........................................97 6. GENERAL DISCUSSION AND FINDINGS ........................ 101 6.1 DAY AND NIGHT VISION ............................. 101 6.2 THE VALIDITY OF CURVATURE TESTING ................ 103 6.3 HORIZONTAL CURVES ................................ 103 6.3.1 Implications For Curve Safety .............104 6.4 CLOSE FOLLOWING .................................. 105 6.5 SPEED BEHAVIOUR IN RURAL AREAS ...................106 6.6 FUTURE RESEARCH IN SPEED PERCEPTION ..............101 6.6.1 Variables Not Tested To Date ..............108 6.6.2 The Next Step .............................109 6.6.3 New Directions ............................ 110 7 . PERCEPTUAL COUNTERMEASURXS ..............................111 7.1 TRADITIONAL APPROACHES TO SPEED CONTROL ..........112 7.1.1 Local Area Traffic Management .............113 7.2 PERCEPTUAL COUNTERMEASURES .......................114 7.2.1 The Unobtrusive Nature of Perceptual Countermeasures ........................... 114 7.2.2 The Effectiveness of Perceptual Countermeasures ........................... 116 7.2.3 Limitations With Perceptual Countermeasures ...........................117 7.3 SPEED PERCEPTION COUNTERMEASURES .................118 7.3.1 Transverse Road Markings ..................118 7.3.2 Transverse Markings with Rumble Bars ......121 1.3.3 Lane Width Reductions ..................... 121 7.3.4 Longitudinal Edgeline Treatments ..........124 7.3.5 Lateral Edgeline Treatments ...............125 7.3.6 Guideposts and Chevron Signs