itsa’s 13 th annual meeting- may 22, 2003 evaluation of a nighttime directional guidance system...

ITSA’s 13th Annual Meeting- May 22, 2003

Evaluation of a Nighttime Evaluation of a Nighttime Directional Guidance System Directional Guidance System

for Heavy Vehicles for Heavy Vehicles

RRichard Hanowski, Ph.D.ichard Hanowski, Ph.D.Virginia Tech Transportation InstituteVirginia Tech Transportation Institute


AcknowledgementsAcknowledgements

• FMCSA funded- DRFH61-00P-00471• Tim Johnson was COTR• Phil Roke served as COTR early in the

project• Paul Rau (NHTSA) provided technical input • VTTI assistance from Miguel Perez, Seth

Cross, Jon Hankey, Walt Wierwille, Andy Petersen, Rebecca Olson, Eryn Perry

Federal Motor CarrierSafety Administration U.S Department

of Transportation


INTRODUCTIONINTRODUCTION


ProblemProblem• Over 3 million single

vehicle roadway departures (SVRD) each year

• Result in 13,000 fatalities and an estimated $100 billion in damage

• Combination-unit trucks are involved in 31,000 SVRD crashes annually

• Out of the 4,847 fatal crashes in 1999 that involved a large truck, the number one driver-related factor was the driver’s failure to keep in the lane


Potential CountermeasurePotential CountermeasureLaser Guidance System

(by Mr. Locke White) – 2 fixed-point lasers (class

3A), positioned on either side of the vehicle

– The laser device emits red “dots” ~ 7.26 m (25 ft) ahead on the pavement

– Dots provide the driver with path prediction information; indicate the vehicle’s path should the driver maintain the current heading


Driver’s ViewDriver’s View

Simulated View


Laser SchematicLaser Schematic


Research ObjectiveResearch Objective

• The goal of this research was to collect data to investigate the effectiveness of this guidance device: – Determining the impact that a laser

directional guidance system has on improving a driver’s ability to maintain directional control

– Assessing the extent to which such a device would enhance or reduce driving performance, workload, and situation awareness

– Determining the attitudes of truck drivers towards the device


Cost ComparisonCost Comparison

Guidance Classification

System type Cost

Infrastructure-based Lateral Departure Warning Systems

CSRS – Rumble Strips

$217/km ($347/mile)

Ferromagnetic markers

$6875/km ($11,000/mile)

Vehicle-based Lateral Departure Warning Systems

SafeTRAC $40,000/truck

Laser Guidance System

$30/truck


METHODMETHOD


OverviewOverview

• To achieve the research objectives, an on-road empirical field study was conducted

• All experimental tasks required driving an instrumented 1997 Volvo, VN-series class 8 tractor with a 14.63 m (48 ft) trailer

• The LG system’s effect on the commercial vehicle driver was measured by evaluating how the driver’s driving performance, workload, and situation awareness changed during exposure to the system


Experimental DesignExperimental Design• Mixed factorial design with one between-

subject variable (Driving Experience, experienced/ inexperienced) and one within-subject variable (Laser Guidance System Status, on/off)

• N=16• Experienced = > 5 yrs; Inexperienced = < 2

yrs• The LG system’s presentation order was

counter-balanced– The test route was divided into quarters of

approximately 96.56 km (60 miles) per quarter – Half of the subjects had the laser presentation

order, on-off-on-off, while the other half had the opposite order, off-on-off-on


Instrumented TruckInstrumented Truck


RESULTSRESULTS


Investigate System Impact On…Investigate System Impact On…

• Lane Keeping Behavior

• Driving Performance Metrics

• Driver Acceptance and Opinions

• Sample of the results are presented; all findings included in final report


Number of Lane DeviationsNumber of Lane DeviationsDriver Experience• Experienced drivers had less than half the

number of deviations than inexperienced drivers (8.75 vs. 17.8)

Experience X LG System Status• When the system was on, number of lane

deviations was reduced for inexperienced drivers (from 20.19 to 15.5; 23.23% reduction)

• No reduction for experienced drivers


Number of Lane DeviationsNumber of Lane Deviations

0

5

10

15

20

25

30

35

?2 yrs ?5 yrs

Driver Experience

Laser Off

Laser On


Mean HeadwayMean Headway• LG Status X Driver Experience• Consistent headway for experienced drivers

when system on or off• Less headway for novice drivers when

system off • Headway increased by 0.22 sec when

system on for novice drivers (~21 ft at 65 mph)

• Unexpected safety benefit for novice drivers?

• Red dots act as extension of truck, or more cautious behavior due to increased cognitive load?


Mean HeadwayMean Headway

0

0.5

1

1.5

2

2.5

3

3.5

?2 yrs ?5 yrs

Driver Experience

Laser Off

Laser On


CONCLUSIONSCONCLUSIONS


ConclusionsConclusions• Lane keeping improvement

– 23% reduction in lane deviations for novice– No reduction for experienced drivers– System may serve as useful training tool for

novice drivers

• Negligible negative impact on driving performance– Possible reduction in SA with initial use– Unexpected benefit of increasing headway

for novice drivers


ConclusionsConclusions• Novice drivers derive most benefit

– Are practical implications of this finding- most lane departure crashes occur with younger drivers (Wang & Knipling, 1994)

– Novice drivers need help most

• Favorable driver opinion• Cost effective countermeasure


Next StepsNext Steps• System has cleared preliminary hurdles, further

research warranted• Look at driver’s re-design suggestions

– Move dot location further out– Increase size of dots– Change color of dots (other than red- color of

taillights)– Automatically deactivate under specified

speed (e.g., 35 mph) where greatest likelihood of lasers path being crossed

• Need to assess driver behavior with long-term use (does long-term use introduce negative behaviors?)

• Other applications for message presentation location?


[email protected]@vtti.vt.edu

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