To our knowledge, this is the first study to conduct a large-scale evaluation of the effectiveness of a widely adopted type of taxicab safety equipment. Our findings suggest cities with camera-equipped taxicabs experience reduced rates of taxicab driver homicides post-installation and compared with cities that do not use cameras. Furthermore, those cities where camera-equipped taxicabs were mandated by ordinance experienced no taxicab driver homicides post-installation whereas the two cities that experienced taxicab driver homicides post-installation, although fewer, were in cities where the dominant (>70% of market) taxicab company implemented a policy of camera-equipped taxicabs. Findings suggest that cities with partition-equipped taxicabs may experience reduced taxicab driver homicide rates compared to nonpartition-equipped other cities.
The observance of a significant reduction in taxicab driver homicides in cities where taxicabs are equipped with cameras, and the more pronounced effect in cities where taxicabs are equipped with cameras as mandated by a city ordinance, was an encouraging one. Based on anecdotal evidence from transportation regulators in cities already mandating cameras by ordinance, transportation regulators are currently considering promulgating city ordinances for their cities that will mandate the use of security cameras in taxicabs. Our findings suggest cities where taxicabs are equipped with cameras could result in fewer taxicab driver homicides particularly in cities with an ordinance mandating taxicabs are equipped with cameras. Furthermore, these findings are consistent with a previous analysis examining news clippings to identify homicides (Chaumont Menéndez et al. [2013]). Specifically, results of the news clippings analysis were concordant with the current study with respect to an observed effect of cameras in possibly reducing citywide taxicab driver homicide rates, but inconclusive for the effect of partitions.
Nearly all of the cities studied had installed partitions in taxicabs by 1996, which limited the data available to examine the pre-post differences in homicide rates. However, 15 years’ worth of homicide rates in partition cities compared to control cities, after adjusting for city homicide rates and temporal patterns in taxicab driver homicide rates, revealed no statistically significant difference.
The primary limitations to the study are due to the ecological study design: (1) we could not estimate individual risk of homicide for taxicab drivers across safety equipment types and (2) the lack of uniform data in the crime reports on homicide circumstances precluded more detailed analyses. Significant strengths of this study are the 15-year time span, systematic collection of data in 20 major US cities, pre-post design that includes use of comparison cities with neither camera-equipped nor partition-equipped taxicabs, and statistical analysis that accounts for serial correlation of data that adjusts for two crucial covariates. Additionally, in working with city regulators and counting only licensed drivers, we were able to assume the drivers were in taxicabs installed with required safety equipment. The study and its findings make a significant contribution to understanding the possible effect of taxicab safety equipment on taxicab driver homicides.
Taxicab driver personal safety in Seattle and King County, Final report and recommendations. The report of the Taxicab Advisory Group Committee on Driver Safety to the Director of the Department of Executive Administration for the city of Seattle. June 18, 2004.