An example of this sort of TIM performance analysis comes from the Arizona DPS. Arizona has applied this same concept to examine TIM performance more closely by incident severity in the metropolitan Phoenix area. The figure below compares performance by incident (in this case crash) severity over a 3-year period between 2011 and 2013. Categorization of crashes by severity was as follows: minor crash (ICT of 30 minutes or less), intermediate crash (ICT between 31-119 minutes), and major crash (ICT 120 minutes or more). It should be noted that as the crash severity is categorized based on ICT, the categorization took place after calculation of the ICT performance measure (as opposed to categorizing the incident severity at the time of the incident based on the incident characteristics).
The figure below illustrates that over the 3-year period, more crashes fell into the “minor” crash category, while fewer crashes fell into the “intermediate” and “major” crash categories. These results show that performance in terms of incident clearance improved over the 3-year period, as responders were able to clear incidents more quickly. This is particularly visible for the 2013 data, when overall there were more crashes than in 2011 and 2012. Yet in 2013, there were the least number of intermediate and major crashes.
Arizona has also examined TIM performance by injury severity, as was discussed in a section on the legal and institutional issues on TIM performance measures. Please click here for a presentation of these results.