Download Human Factors Progress

Human Factors Progress
IDS Project
June, 2004
Nicholas Ward
Mick Rakauskas
Jason Laberge
Janet Craeser
HumanFIRST Program
Human Factors Tasks
Analyze problem
Task analysis
“What are the task elements of crossing an intersection?”
“Where in this sequence in the task failing?”
“Who is most at risk?”
Information analysis
“What information supports task behavior?”
“Which information is misused or missing?”
Simulate case site
Propose interfaces and simulate candidate
Review previous solutions
“What has not worked before?”
Evaluate candidate interface
Task Analysis
Detect intersection
Decelerate and enter correct lane
Signal if intending to turn
Detect and interpret traffic control device
Detect traffic and pedestrians
Detect, perceive, and monitor gaps
Accept gap and complete maneuver
Continue to monitor intersection
Target Population
Older drivers (> 65 years) have a
high crash risk at intersections
Drivers > 75 years had greatest accident
involvement ratio (Stamatiadis et al., 1991)
Drivers > 65 years 3 to 7 times more likely
to be in a fatal intersection crash
(Preusser et al., 1998)
Drivers > 65 years over-represented in
crashes at many rural intersections in
Minnesota (Preston & Storm, 2003)
Abstraction Hierarchy
Aggregate
Detailed
Functional
Purpose
Physical Form
Concrete
Physical Function
General
Function
Abstract
Function
Abstract
Whole
Subsystem
Component
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Safe transport
Efficient transport
Rapid transport
Pleasure
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Field of safe travel and field zone ratio (time, distance,
energy, acceleration and force balances)
Probabilistic balance of risk and success
Performance and cost balance
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Stochastic properties of traffic
Traffic dynamics (traffic stream stability)
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Vehicle dynamics
Regulatory constraints
Norms and cultural conventions
Other driver intent
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Destinations
Paths and routes
Visibility
Coefficient of friction
Obstacles and associated hazard severity
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Environment types (dusk, dawn)
Weather conditions
Traffic density
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Road type (rural, urban, suburban)
Road boundary (sidewalks, shoulders)
Roadway furniture (medians, guardrails)
Road surface treatment (asphalt, concrete)
Intersection type (signal, sign, uncontrolled)
Gap density
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Vehicle state (acceleration/braking capabilities,
steering radius, weight/length/width, tire condition)
Relative position, velocity and acceleration of other
vehicles, pedestrians and road boundaries
State variables describing vehicles, pedestrians and
animals
Lanes
Maneuver type (left/right turn, straight) of self and
others
Pavement surface conditions
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Particular
Particular
Particular
Particular
Particular
Particular
Particular
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Lane width
Curve geometry
Surface features
Shoulder features
Median width
Intersection angle/grade
Number of driveways
Sign/signal characteristics
Intersection sight distance
Proximity to other intersections
Average daily traffic
Presence of other devices (lights, rumble strips,
stop-ahead signs, etc.)
Speed limit
car, truck, bike
dog, cat, deer
gap (actual size, safe or unsafe)
lane
sign/signal
pavement surface conditions
maneuver
Generic Support
A. Intersection / Control device
B. Vehicle presence
C. Vehicle speed, distance, time
D. Size of gap in traffic
E. Safety margin of gap

(specified location in traffic)
Minnesota Context
In Minnesota, most drivers stop before
proceeding (Preston & Storm, 2003)
57% stopped in 2296 rural thru-STOP accidents
87% of right angle crashes at US 52 and CSAH 9
occurred after the driver stopped
NOT a violation problem
Instead, a gap acceptance problem
Detecting vehicles (speed, distance, time)
Perceiving gap size (and location)
Judging safe gaps
Minnesota Location
Road Network
Intersection
Elevation
Crossing
Demonstration
Interface Task
Design Tenets
Prohibitive (not permissive).
Decision remains with driver.
Design for worst case.
Use MUTCD sign guidelines.
Consider diverse range of option rather than refine a concept.
Expert panel review of concepts
Everyone had own perspective.
No consensus for best sign.
Some signs ejected.
Interface demonstration
IDS TAP
MN Pooled fund
MUTCD
Revised design
Four Prototypes
Hazard Beacon
•Flashing sign
activates when
intersection is unsafe.
•System tracks
arrival time
(or speed)
of lead vehicle
Speedometer
•Speed monitor
for lead vehicle.
•Flashes red when
near or far-side
vehicle is speeding.
Hybrid
•Arrival time
countdown for
lead vehicle.
•Prohibitive
symbol relative to
maneuvers based on
near and far-side
traffic conditions.
Spit-Hybrid
•Median position
with logic for North
•Left nearside
position for North
and South.
Baseline
Hazard Beacon
Speedometer
Hybrid
Split Hybrid
Conclusion
Task
S03 O N D J04 F M A M J J A S O N D J05 F
Intersection
Select X
Task Completed:
Intersection
Intersection selected
Simulator
X X X X
and
simulated with high
Intersection
Demo
X
Geospecific accuracy.
intersection
Interface
Simulate
X X X
Interface
Task Completed:
Demo
X
•Interface concepts generated.
Interface
Revise
X X
Interface
Evaluation
Develop
X X X
Simulation
Develop
X
Protocol
Recruit &
X
Pilot
Task on schedule:
Conduct
X X
Study
•Experiment outlined.
Analyze
X X
•Interface logic tested.
Data
•Traffic models under
Report
review (gaps).
Draft Report
X X X X X X