The Alabama Highway Safety Plan (HSP) is a product of the ADECA Law Enforcement and Traffic Section (LETS). They have contracted with CAPS to produce this plan for well over the past 15 years. CAPS uses the CARE system to provide problem identification services, essentially using the following process:
- Run frequency distributions over all of the data elements unfiltered to assure that the data elements are sound and producing reasonable results.
- Run frequency distributions for all relevant subsets and variables. Subsets of data would include alcohol, pedestrian, motorcycle, bicycle, speed, and as many other crash causes and sources as were being considered for countermeasure funding.
- Using the CARE IMPACT module, compare these subsets with their complements or with other subsets in order to surface anomalies in the data. (For example: this analysis would surface not only the fact but also the extent to which alcohol crashes are over-represented on Saturdays and in rural areas. The information mining capability of IMPACT establishes statistically significant results in over 100 crash data elements, each of which provides a “piece of the puzzle” in establishing how to respond to alcohol crashes. Similar results are found with most other crash types as well.)
- Perform in-depth analyses on variables that surfaced using CARE’s cross tabulation and automated filter generation capabilities. (For example: a cross tabulation of alcohol crash severity by the rural-urban variable, which shows that alcohol crashes in the rural areas are more severe than their urban counterparts.
- Extend the analyses to determine specific locations that might be addressed by selective enforcement countermeasures. This involves examining all roadways within a given region and selecting those that had particular problems in the crash type under consideration. Generally, speed and alcohol are the two crash types considered for selective enforcement.
The goal of this process is to first identify which type of crashes are causing the greatest problems in terms of injury and fatality. At that point, the analysis can determine the best countermeasures and how they can best be applied. The analysis data includes the who, what, when, where and why of specific types of crashes. Countermeasures apply this information so that funds that are expended hit the right target in terms of producing a maximum benefit for the roadway users of Alabama.
In recent years ADECA/LETS has given increased emphasis to problem location identification. This emphasis has increased to the point that the major part of the HSP now consists of specifications of locations that are over-represented in speed related and alcohol related crashes. This is accomplished by separate CARE runs in that the characteristics and locations of speed related crashes are generally different from those of alcohol. These locations, usually defined in five-mile sections, are further illustrated on maps to make it easier for officers in the field to identify the best areas and routing for selective enforcement. This is closely organized by the regional Community Traffic Safety Program (CTSP) coordinators, who assure that overtime funding for selective enforcement in their respective areas concentrates on the problem areas.
In summary, the HSP is an operational document that is used in the field to implement the best-known strategies for ADECA/LETS resource allocation. CAPS will continue to serve ADECA/LETS in providing CARE and traffic safety expertise in performing the problem identification, GIS mapping, and documentation required to generate the best possible HSP.