SensorFriendly Vehicles and Highways: An Initial Step in VehicleRoadway Cooperation

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Sensor-Friendly Vehicles and Highways An
Initial Step in Vehicle-Roadway Cooperation

• Jim Misener
• PATH Program-Wide Research Meeting
• October 17, 2001

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Outline

• Motivation/Background
• Candidate Concepts/Experiments
• LEDBM Taillights
• IR Fluorescent Pant
• Passive License Plates
• Passive Corner Cube Reflectors Spaced
  Tetrahedral Array Retroreflectors (STAR)
• Summary and Conclusions

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Motivation Sensor Friendly Vehicles and Roadways

• Premise Infrastructure Can Supplement Emerging
  Driver-Assist Systems
• Clutter/Misidentified Targets is the Problem
• Forward Collision Warning Systems with Automotive
  Radar
• Lane Departure Warning Systems with Optical
  Sensors
• Benefits
• Improved Effectiveness
• Quicker Deployment
• Effectiveness Means User Acceptance
• Lives Saved

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MOU 368 (Sensor-Friendly Highways) and US DOT
Contract (Evaluation of Sensor-Friendly Vehicles
and Roadways to Support Intelligent Vehicle
Services)

• Objectives
• Overarching
• In support of IVI, investigate cooperative
  systems to improve the performance of intelligent
  vehicles
• Specific
• ID alternative passive devices and marking
  methods for vehicles and roadway features
• Evaluate the potential of IDd concepts
• Assess Incremental costs and benefits,
  availability, and deployment time
• Propose strategy for achieving a national
  deployment
• to include a program of research, ranking,
  development, field test, evaluation, and
  deployment

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Vehicle-Roadway Environment Potential Problems
Due to Geometrics

• Target Loss in Tight Turns
• Deceleration Due to Vehicles in Adjacent Lanes
• Acceleration in Merging/Lane Change Situations
• Target Loss on Downgrades
• Cut-Ins
• Vehicle Enters Lane at Short Range then
  Decelerates
• Other Sources of False Alarms
• Clutter Identified as Target
• Ambiguous Range Objects
• Vehicles Outside FOV
• side lobes

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Radar Performance In Roadway Environment San
Rafael Bridge

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Another Illustration...
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Some Observations

• Signs and Other Roadside Features Detected with
  Some Frequency
• overpasses and sign panels
• electroliers (cylindrical shape, low RCS)
• chainlink fences
• painted road markings
• however, at close range, occasional detection of
• bridge trusses
• traffic signals
• smaller sign panels
• Common Precursor to Detection Periodic and
  long-duration dihedral or trihedral patterns

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Technologies (Categorized)
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Light Emitting Diode Brake Messaging (LEDBM)
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LEDBM Supplement to Forward Collision Warning

• LEDBM System (Two Photodiode Assemblies)
• LEDBM Prototype Specifications
• Operating Range 0 60 m
• Azimuth up to /- 12.5 degrees (adjustable)
• Elevation up to /- 12.5 degrees (adjustable)
• Tracking 1 target

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Proof of Concept Tests
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Varying Roadway and Traffic Conditions Around
Curve
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Varying Roadway and Traffic Conditions
Elevation Change
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Varying Roadway and Traffic Conditions Dense
Traffic
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Rapid and Gradual Decelerations
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Cut-Ins
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Selected Results
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IR Fluorescent Paint
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Fluorescence

• Definition
• Absorbs light of one color, then emits light of
  another color
• Application
• Metal oxide pigments added to paint or beads
  (glass or plastic) beads
• Makes lane markings detectable by their
  fluorescence

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Fluorescent Lane Markings
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Findings

• From Laboratory Experiments
• Signal and signal-to-noise ratio are easily
  adequate for look-down or short look-ahead
• But may not be adequate for distant look- ahead
  using economically viable equipment
• Sufficient codespace is available for simple
  labels, e.g., left vs. center vs. right markers
• We require fluorescent pigments whose sensitivity
  is not suppressed by sunlight

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Passive License Plates
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Passive License Plates Without Dielectric Filler
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PLP High Radar Reflection at 45 Degrees Off
Center
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Passive License Plate Test Car
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Vehicle Tests of Radar Signal from PLP
With Passive License Plate
With Regular License Plate

• Red arrow shows magnitude of return from target
• Both at 0 degrees angle of incidence

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Radar Signal from PLP
With Passive License Plate
With Regular License Plate

• Red arrow shows magnitude of return from target
• Both at 22.5 degrees angle of incidence

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Findings

• In the laboratory, PLP tests showed high target
  returns at plus-or-minus 45 degrees
• Potential reliable point source signature in
  the middle of target vehicles, regardless of
  curvature
• In the field, PLP tests worked well only near
  zero degrees angle of incidence
• Further and more extensive testing required

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Passive Corner Cubes
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Corner Cube

• Radar Cross Section (RCS) proportional to L and
  to wavelength.
• Our test corner cubes RCS 6.6 m2

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Spatial Tetrahedral Arrays of Reflectors (STAR)

• Unique arrays of corner cubes corresponding to
  infrastructure markings
• 77 GHz 0.15-in wavelength -- easy to create
  relatively cheap corner cubes
• External beam shaping
• In-Vehicle
• Roadside

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Test Vehicle
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Roadside Corner Cube Markings
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Radar Map for six equally spaced Corner Cubes
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Radar Map for Corner Cube Pattern 110101
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Findings

• Corner Cube Patterns were well detected and
  distinguished by Radar Sensor.
• Would work well for encoding roadway objects.

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Summary and Conclusions

• Candidate Concepts Developed and Evaluated
• LEDBM Taillights
• IR Fluorescent Pant
• Passive License Plates
• Passive Corner Cube Reflectors Spaced
  Tetrahedral Array Retroreflectors (STAR)
• Technology and Cost Benefits (TRR Article)
  Quantified
• Prototypical, Preliminary
• Sensor Friendly has High Potential
• Near Term Enabler of Emerging Forward Collision
  Warning Safety Systems
• Perhaps the Only Way These Promising Safety
  Systems Will Effectively Work