Evaluation of lane departure warnings for drowsy drivers

Ksenia Kozak, Jochen Pohl, Wolfgang Birk, Jeff Greenberg, Bruce Artz, Mike Blommer, Larry Cathey, Reates Curry

Ford Motor Company, Dearborn, MI

報告者：楊子群

INTRODUCTION

Reduce to crashes of traffic. Many roadway departure crashes take place in light traffic situations

and good weather conditions. Drowsiness is frequently reported driving conditions: Night-time driving In monotonous

51% of drivers reporting that they driving have feeling drowsy in the past year.

　　　　　　　　　　　　　　　　　　　 (Horne & Reyner, 1995)

About 100,000 crashes annually in which police cited driver drowsiness, resulting in about 1,500 fatalities.

(NHTSA data, Royal, 2002)

目的 LDW is to warn drivers if they are unintentionally drifting out of their

lanes.

Designed to warning effectiveness and customer acceptance when the unintended lane departures(drowsy driving).

-方法

設備

Ford’s VIRtual Test Track Experiment(VIRTTEX)

=>液態驅動能源， 6軸自由移動的基本駕駛模擬車體是採 2000 Volvo S80

環境 駕駛的地點為模擬部分晚上時候的洲際公路。 駕駛被要求駕駛於右線車道，其中車道寬為 12英呎。 每個方向的道路是由兩條道路所構成。很快地，出現在左邊道路交通超車，其中對向交通不互相影響。交通密度是非常清楚的。

受測者 30位 條件：1.都有駕照2.晚上六點後不能吃咖啡因的食物3.穩定的睡眠週期4.實驗前一晚不能睡覺 (23個小時 )--用 wrist-actimeter來監視睡覺總數，並收集很多個晚上的肢體動作。

Drowsiness Measures

Physiological measure of eye closure(PERCLOS)=>測量睡意 ( 漸漸闔上眼睛=>被定義為在 1 分鐘內，闔眼時間的比例為 80-100%)=>PERCLOS value of 8% was used to define a drowsy driver(Grace and Steward, 2003).

Drowsiness Measures

Psychomotor Vigilance Task(PVT) 醫療精神警戒工作

Drowsiness Measures

Karolinska Sleepiness Scale (KSS)-卡羅林斯卡嗜睡量表

ISCAN Eye Tracker-眼動追蹤儀

Lane Departure Warnings

Control 【 1 】 目前現有=>Steering Wheel Torque HMI 【 2 】+Rumble Strip Sound(隆隆聲 ) 【 3 】- Vehicle driving over gapped rumble strips at 65 mph.

+Steering Wheel Vibration(震動 ) 【 4 】- 15 Hz vibration with 2 Nm peak amplitude and duration of 1.5 s.

+Head Up Display HMIs 【 5 】

實驗設計

Reaction time to warning

Magnitude of lane departure

Time spent outside the lane

experiment

Small yaw

實驗設計

Small yaw

資料收集

Reaction time to warning

Lane excursions

資料收集

Reaction time to warning

Lane excursions

超出界線 回到界線內

Maximum lane excursion

Integrated lane excursion

RMS lane excursion

The time spent outside the lane

實驗程序1) Watched a safety video.

2) Signed a consent form.

3) Initial training with a computer.

4) Four LDW HMIs for training at 5 min.

5) Estimated of sleepiness level.

6) Estimated of three sustained reaction time tasks(15, 75, 135min).

7) Experiment start.

8) Asked their perception : Helpfulness Intuitiveness Acceptability Whether they would like this system in their vehicle.

結果All participants was drowsy of measured by a PERCLOS value greater than or equal to 8%.

Reaction Time to Warning-Significantly reduced the RT almost in half from a mean of 1.17 to 0.62 s (ANOVA, p<0.05).

A

A A(p = 0.06)

A

B(p < 0.05)

Post-hoc t-tests

結果 Lane Excursions- Integrated lane excursion was significantly smaller (p < 0.05) when a LDW was

present. No warning =>4.44 ft-s LDW was present =>2.44 ft-s

Post-hoc t-tests:Steering Wheel Vibration HMI was significantly different from no warning (p<0.05).

- Other: Maximum lane excursion RMS of the lane excursion Total time outside of the

=> Not significantly.

結果 Subjective Assessment

Vibration and the Rumble Strip HMIs higher average(p<0.05): helpfulness acceptability scores

Drivers noticed only 32% of all Torque warnings.

(All other HMIs were noticed at least 98%(p < 0.05))

討論

Steering Wheel Vibration by the Steering Wheel Torque, was found to be the most effective HMI for LDW in drowsy drivers.Faster reaction timeDecrease in the magnitude of the lane excursion.More high acceptable to the drowsy drivers.perceived as helpful.

Rumble Strip Sound HMI advantages(優點 ) were also apparent.Decreasing the reaction time.Roadway departure crashes by 30-50% (Jeftic et al., 2003).

貢獻 PERCLOS能量測出 drowsiness程度。 能有效控制道路偏移的數量 (但有受測者建議能自行操控偏

移 )。 了解使用何種介面能讓駕駛者確實及正確反應。

結語

時間的原因或許不能將所有介面有效呈現出其效果，或許將時間拉長會有不同的感受。