Upload
others
View
7
Download
0
Embed Size (px)
Citation preview
Examining visual behavior of drivers while using adaptive cruise control on
commercial motor vehiclesKevin Grove
Center for Truck & Bus Safety
Virginia Tech Transportation Institute
Adaptive Cruise Control (ACC)
�Automation technology that can control speed and headway on heavy vehicles � Radar mounted on front bumper tracks lead vehicle
� Included in heavy vehicle ADAS products such as OnGuardTM or Wingman®
� Newer generations include cameras with object detection for alerts, but not for ACC
9/18/20189/18/20189/18/20189/18/2018
2
ACC Operation
�Driver selects a speed setting
�If slower lead vehicle present, ACC will reduce speed to maintain a safe headway
�If faster lead vehicle present or no lead vehicle present, maintains set speed
9/18/20189/18/20189/18/20189/18/2018
3
How Do Drivers Use ACC?
�ACC allows driver to “follow” a lead vehicle with headway control
�As a low level automation technology, drivers should maintain full awareness
�In the real world, drivers attention may be different when using ACC
�Could impact ability to react in critical situations
9/18/20189/18/20189/18/20189/18/2018
4
Data on ACC Usage
�As part of a NHTSA study VTTI collected naturalistic data from 150 trucks equipped with OnGuardTM or Wingman® AdvancedTM
products
�Video of driver’s face whenever truck in motion
�Possible to evaluate visual behaviors � With and without cruise control active
� During car following and non-car following
9/18/20189/18/20189/18/20189/18/2018
5
VTTI’s Data Collection
9/18/20189/18/20189/18/20189/18/2018
Location of
Meritor WABCO
OnGuardTM
6
VTTI’s Data Collection
9/18/20189/18/20189/18/20189/18/2018
WABCO
7
Defining Car Following
�Defined “car following” based on radar data of lead vehicle� Car following with ACC if system controlled headway for at least 30 seconds
� Manual car following if driver keeps truck within 4.5 seconds headway for 30 seconds while distance oscillated
9/18/20189/18/20189/18/20189/18/2018
8
Data Sampling and Analysis
�Sampled 3,000 thirty second windows across four conditions
9/18/20189/18/20189/18/20189/18/2018
Following Lead
Vehicle
Not Following Lead
Vehicle
Cruise Control ActiveAdaptive Cruise Control
(1000)
Standard Cruise Control
(500)
Cruise Control
Inactive
Manual Car Following
(1000)
Manual Driving
(500)
Status of Lead Vehicle
Sta
tus
of
Cru
ise
Co
ntr
ol
9
Visual Metrics
�Total eyes off road time (TEORT)� Within each 30 second window
�Average duration of off-road glances� With incomplete glances at the start or end of 30-second windows
removed
�Rate of off-road glances� With incomplete glances at the start or end of 30-second windows
removed
9/18/20189/18/20189/18/20189/18/2018
10
One-factor Comparisons
�ACC vs. Standard cruise control
�Manual car following vs. Manual non-car following
�ACC vs. Manual car following
�Standard cruise control vs. Manual non-car following
9/18/20189/18/20189/18/20189/18/2018
11
Two-factor Comparisons
�All cruise control usage vs. All manual driving� Combine ACC and standard cruise control
� Combine Manual car following and manual driving
�All car following vs. all non-car following� Combine ACC and manual car following
� Combine standard cruise control and manual driving
9/18/20189/18/20189/18/20189/18/2018
12
Average TEORT
9/18/20189/18/20189/18/20189/18/2018
6.1 6.75.3
6.1
0.0
5.0
10.0
15.0
20.0
25.0
30.0
ACC Standard Cruise
Control
Manual Car
Following
Manual Non-Car
Following
Tota
l D
ura
tion
Ey
es O
ff F
orw
ard
Road
way
(sec
on
ds)
Event Type
13
Average Glance Duration
9/18/20189/18/20189/18/20189/18/2018
1.07 1.090.97 1.01
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
ACC Standard Cruise
Control
Manual Car
Following
Manual Non-Car
Following
Mea
n G
lan
ce D
ura
tion
(se
con
ds)
Event Type
14
Average Rate of Off-road Glances
9/18/20189/18/20189/18/20189/18/2018
1.81 2.001.74 1.91
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
ACC Standard Cruise
Control
Manual Car Following Manual Non-Car
Following
Off
-Road
Gla
nce
Rate
per
10 S
econ
ds
Event Type
15
ACC vs. Manual Car Following
�While following vehicles drivers spent more time looking away from the road when using ACC
�The additional time was due to longer glances away from the road� No difference in rate of glances away from road
9/18/20189/18/20189/18/20189/18/2018
16
ACC vs. Standard Cruise Control
�While ACC controlled headway drivers spend less time looking away from the road
�The additional time was due to more frequent glances away from the road� No difference in average glance duration off-road
�Have a lead vehicle present makes drivers pay more attention
9/18/20189/18/20189/18/20189/18/2018
17
Takeaways
�Visual behaviors during ACC usage was different compared to standard cruise control or manually following a vehicle
�While differences were small across the sampled drivers, worth investigating further� Conditions such as drowsiness could have additional impact
� Individual drivers could exhibit larger differences
9/18/20189/18/20189/18/20189/18/2018
18
Takeaways
�ACC a popular technology with truck drivers and has been available on heavy vehicles for several years
�As ADAS technology develops there could be new additions that take over additional functions� Steering control
� Platooning
9/18/20189/18/20189/18/20189/18/2018
19
Takeaways
�Relatively minor differences observed here could become larger as automation takes over additional functions
�As automation progresses we need to ensure drivers stay engaged when they are expected to
�Particularly important on heavy vehicles that could weigh 80,000 pounds or have compromised brakes
9/18/20189/18/20189/18/20189/18/2018
20
Thank you!
9/18/20189/18/20189/18/20189/18/2018
21