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Research Towards Taxicab Driver Safety

Cammie Chaumont Menéndez, PhD September 23, 2013 Menéndez, PhD August 3, 2012. Research Towards Taxicab Driver Safety. Taxicab Driver Safety Issues. Workplace Violence Taxicab drivers have among the highest homicide rates of any occupation Transportation-related Events

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Research Towards Taxicab Driver Safety

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  1. Cammie Chaumont Menéndez, PhD September 23, 2013 Menéndez, PhD August 3, 2012 Research Towards Taxicab Driver Safety

  2. Taxicab Driver Safety Issues • Workplace Violence • Taxicab drivers have among the highest homicide rates of any occupation • Transportation-related Events • Higher rates of motor vehicle crashes

  3. Occupational Homicide Rates*All Workers and Taxicab Drivers *Numerator: BLS Census of Fatal Occupational Injuries from Annual Reports; Denominator: Current Population Survey

  4. Occupational Transportation Fatality Rates* for All Workers and Taxi Drivers Taxi Drivers All Workers *Numerator: BLS Census of Fatal Occupational Injuries from Annual Reports; Denominator: Current Population Survey

  5. Workplace Violence and Taxicab Drivers: Research Opportunities • Evaluating security camera components • Evaluating the effectiveness of security equipment • At a city level (macro) • At an individual level (micro)

  6. . Partnerships • IATR • TLPA

  7. Multi-City Study Hypotheses • Primary Installing cameras results in a reduction in citywide taxicab driver homicide rates -post-installation -compared to cities without cameras • Secondary Cities with partitions experienced reduced taxicab driver homicides rates compared with cities without partitions

  8. Study Population • Major cities enrolled • Must have population >250,000 • Within MSAs, largest city selected • City that maintains taxicab licenses

  9. Data Elements • Taxicab driver homicide count • Two data sources: news clippings and crime reports • Licensed taxicab count • Safety equipment status • City homicide rate • Collected per city and per year

  10. Study Design/Analysis • Retrospective longitudinal time series analysis • 1996-2010 • Pre-post with comparison group • Poisson distribution with GEE • Dependent variable: taxicab driver fatality rates • Independent variables: safety equipment status

  11. Results: News clippings Data

  12. Taxicab Driver Homicides in Camera Cities Pre- and Post-Installation 2 4 4 4 2 4 1 1 2 0 *indicates cities with an ordinance mandating cameras. Numbers above columns indicate number of homicides.

  13. Modeling intervention effects on city-wide taxicab driver homicide rates *testing difference in taxicab driver homicide rates post-installation vs. pre-installation of cameras †testing difference in taxicab driver homicide rates in camera cities compared to control cities §testing difference in taxicab driver homicide rates in partition cities compared to control cities

  14. Results: Crime Report Data

  15. Taxicab Driver Homicides in Camera Cities Pre- and Post-Installation *indicates cities with an ordinance mandating cameras. Numbers above columns indicate number of homicides.

  16. Modeling intervention effects on city-wide taxicab driver homicide rates *testing difference in taxicab driver homicide rates post-installation vs. pre-installation of cameras †testing difference in taxicab driver homicide rates in camera cities compared to control cities §testing difference in taxicab driver homicide rates in partition cities compared to control cities

  17. Conclusions • Both data sources provide congruent findings • The installation of cameras seems to play a role in reducing taxicab driver homicides at a city level • There is no evidence to suggest partitions play a role in reducing taxicab driver homicides at a city level

  18. What Now? • Multiple approaches are best for safety • Policies and procedures • Safety training • Requirement for licensing • Trip sheet • Frequent bank deposits • Safety equipment • Cameras with decals, partitions • Cashless systems • GPS • Silent alarm

  19. Camera Evaluation Study

  20. Project Objectives • Develop minimum parameter requirements for taxicab camera system evaluation. • Use minimum requirements to evaluate 8 sample taxicab cameras, and disseminate evaluation report. • Determine future areas to improve taxicab cameras. • Develop technical guidelines for taxicab camera selection and usage.

  21. Preliminary Results • Reference Camera Photo Resolution Thresholds Daylight (Color Camera): 83.3 Daylight (Infrared Camera): 68.7 Dark (Infrared Camera): 61.0 Dark with Backlit (Infrared): 89.2 Sunset via Rear Window (Color): 57.5 Sunset via Rear Window (Infra): 57.6 • These ranges are comparable to the Victoria, Australia standard • The threshold range is a challenge for regular resolution cameras (480 vertical pixels) to keep rear seat image quality above the thresholds

  22. Preliminary Results • Reference Camera Photo Highlight Dynamic Range (EV): Daylight (Color Camera): 5.53 Daylight (Infrared Camera): 4.58 Dark (Infrared Camera): 5.58 Dark with Backlit (Infrared): 5.46 Sunset via Rear Window (Color): 4.83 Sunset via Rear Window (Infra): 4.54 • Mean highlight dynamic range of 6 light conditions=5.01 EV

  23. Preliminary Results • Reference Camera Photo Shadow Dynamic Range (EV): Daylight (Color Camera): 4.32 Daylight (Infrared Camera): 5.54 Dark (Infrared Camera): 4.32 Dark with Backlit (Infrared): 3.99 Sunset via Rear Window (Color): 3.99 Sunset via Rear Window (Infra): 2.99 • Mean =4.19 EV, 0.82 EV lower than the Highlight Dynamic Range. Human eyes are less tolerant to highlight washout than under exposure cab face images.

  24. Preliminary Results • Reference Camera Photo Lens Distortion Threshold (%): Daylight (Color Camera): 45 Daylight (Infrared Camera): 45 Dark (Infrared Camera): 30 Dark with Backlit (Infrared): 45 Sunset via Rear Window (Color): 30 Sunset via Rear Window (Infra): 15 • Mean =35%. Distortion thresholds are rather diverse. • Human eyes are less sensitive to image distortion in face recognition. • Most of sample camera distortions are below the thresholds.

  25. Preliminary Results • All of the flash memory cards passed 5 meter/72 hour waterproof tests. • Experiment was conducted in fresh water. • Memory cards survive 1000 F/5 minute test within a 1-inch thick “Microtherm” thermal insulation chamber.

  26. Summary • The determined photo resolution range (57.5-89.2 LW/PH) is comparable to the Victoria, Australian standard (108 pixels per 30cm-picture height). • Real-world resolution reductions of regular cameras (480 vertical pixels) due to lens quality and other factors, may reduce the real resolution to below the resolution range determined by photo evaluators. • Human evaluators seemed more able to identify under-exposed in-cab facial images than washed-out ones.

  27. Summary • Lens distortion seems to be a less important factor in cab face identification. • 1/30-1/40 second shutter speed threshold seems not to be difficult for most of sample cameras to achieve. • Flash memory cards survive 5 meter/72 hour fresh water test. • Fire resistant chamber might protect memory cards in a 1000 F/5 minute cab fire profile.

  28. Taxicab Driver Survey Study • Study Objectives • Evaluate events of workplace violence among taxicab drivers • Fare evasion, theft, carjacking, robberies, assaults • Describe the occurrence of motor vehicle events among taxicab drivers • Crashes in the past 2 years • Describe the risk of motor vehicle events among taxicab drivers • Job demands, road safety behaviors, safety climate

  29. Study Progress • 30-minute survey developed and peer reviewed • 60-page protocol submitted for more extensive review (OMB) • In the field conducting interviews in 2014 • 500 drivers in two cities

  30. Thank you! • Acknowledgments • Taxicab Driver Research Team • Very supportive management at DSR and NIOSH • Invaluable efforts of study partners • Contact with any questions/comments Cammie Menendez: cmenendez@cdc.gov ShengkeZeng: szeng@cdc.gov The findings and conclusions in this presentation have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy

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