The previous sections identified the incident characteristics that are most likely to be used when calculating TIM performance measures. The use of other incident characteristics can also be valuable in understanding TIM performance. Additional incident characteristics could include roadway, lighting, and weather conditions; the number of people involved in the incident, the number of response vehicles at the incident scene. These insights into the data could point out situations where additional resources may be required to respond to incidents in these particular situations.Whether towing services were required at the scene is another incident characteristic that could be used to assess performance. If data were to show significantly long clearance times associated with incidents where towing was involved, an agency may consider improving their relationships with the towing community, establishing on-call contracts, tower rotation services, or other mechanisms to reduce the overall times associated with clearance.Indication that an incident occurred in a work zone may be another incident characteristic that can alert any agency to an area where response or roadway safety could be improved, thereby reducing the number of overall incidents and potentially, the response timeframes.
Overall, any number of incident characteristics can be used to further assess an agency’s TIM performance. The caveat, however, is that while they may provide additional insight into the operation of the TIM program, they cost time and money to collect and analyze. In many cases, if data are coming from outside sources, such as law enforcement, these data may not be available or may only exist in free-form text fields, making it difficult to assign them for each incident.
The page titled, A Model Database for TIM Performance Measurement of the website provides a number of examples of how to use the data elements in a model TIM performance measurement database to contextualize, and thus better understand, TIM performance. Specifically, the primary purpose of the page titled, Analysis of Incident Data to Determine TIM Performance, is to illustrate how to stratify TIM data for analysis. Generic examples are given for a wide range of incident characteristics (e.g., incident severity, injury severity, roadway characteristics, lanes involved, time of incidents, vehicles involved, weather, lighting, and surface condition), as well as examples of stratifications on multiple incident characteristics. In addition, the page titled, Example Applications of the Model TIM Performance Measurement Database presents example scenarios and data to illustrate in more detail how to “dig deeper” into the data to better contextualize TIM performance.