Driver Responses to an Infrastructure Based Intersection Collision Warning System

1
Driver Responses to an Infrastructure Based
Intersection Collision Warning System

• Gregory W. DavisFederal Highway Administration,
  Office of Safety RDTMcLean, Virginia, USA

2
The Red-Light Running Problem

• Red-light violations attributed annually
• 200,000 crashes
• 178,00 injuries
• 920 deaths

3
Current FHWA Sponsored Research and Development

• Intersection Decision Support system research
  includes
• Warning the potential red-light violator
• Warning the potential victim of the violator
• Virginia Tech Transportation Institute conducting
  violator warning studies
• FHWA Office of Safety RDT conducting victim
  warning studies

4
Warning Potential Victims

• Warning must come when potential victim is on
  close approach to intersection
• Response to warning must be
• Intuitive
• Rapid
• Robust

5
Research Question

• What would drivers do when given novel,
  unexpected, warning?
• What proportion would avoid collision?
• Would accelerated phase change be enough?
• Are more intense warnings more effective?
• Does driver age matter?

6
Warning Conditions

1. 4 s amber (Control)
2. ½ s amber
3. Immediate red ball with supplemental flashing red
   lights, illuminated stop symbol, and white strobe
   lights
4. Preceding (3) plus in-pavement red lights and
   intelligent rumble strips

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Warning Conditions (continued)

• All warnings triggered at either 215 ft or 180 ft
  from the intersection

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Condition 3
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Condition 4
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Procedures

• Driving Simulator
• Participants told this was a study of traffic
  signal timing
• Drove through 32 signalized intersections
  separated by ½ miles
• Infrequent need to stop
• No signal changes to red near intersection
• Warning occurred at 33rd Intersection

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Procedures (continued)

• Drivers instructed to
• Maintain 45 mph
• Continue straight on the current road
• Obey all traffic laws
• Otherwise, drive as they normally would

12
Research Design

• Four independent (between) groups design
• Half the participants were over 65 years of age
  or older
• Groups balanced for age and gender

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Results
Condition Not Delayed Delayed
1. Control (4 s Amber) 69 31
2. ½ s Amber 51 49
3. Flashing Lamps and Sign 39 61
4. Added Rumble Strips and In-Road Lights 33 67
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Results (continued)
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Conclusions

• A substantial proportion of drivers will respond
  sufficiently if given a compelling warning
• However, more drivers responded than expected in
  the control condition
• All driver age groups may benefit age
  difference for reaction times was not detected
• Further research and development is needed to
  determine driver responses in platoons
• A Field Validation Study is currently underway at
  VTTI