U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Low-Cost Safety Enhancements for Stop-Controlled and Signalized Intersections
9. Systematic Deployment—The Process
- Select the low-cost countermeasures to deploy using a systematic process. It could be all or a few of those previously listed. As an example, assume that improving signs and markings at stop-controlled intersections is one of the countermeasures selected.
- Identify candidate intersections for countermeasure application. Sign and marking countermeasures can be implemented on four categories of intersections: State urban, State rural, local urban and local rural stop-controlled intersections. For each of these categories, the fatalities per 100 crashes and number of crashes per intersection (Tables 7 and 8) are developed from 5 years of data for the type of crash the low-cost countermeasure is intended to impact (all crashes for sign and marking countermeasures at stop-controlled intersections). Establish a crash threshold for each category based upon probable cost effectiveness of the countermeasure; the relationship between the crashes per intersection, cumulative intersections, and cumulative statewide crashes; the estimated funds available; and the number of intersections where the State may realistically implement countermeasures over the next few years. The threshold may be adjusted to consider entering AADT if that data is readily available. As an example, in general, a threshold of 5 crashes in 5 years for rural stop-controlled intersections may be established, but intersections with a low AADT, say less than 2000, could have a threshold of 4 crashes. Candidate intersections are those at or above the threshold.
- Assess the potential impact. Using the number of candidate intersections at or above the threshold, the fatalities per 100 crashes, the countermeasure crash reduction factor, and the estimated number of candidate intersections that will be improved, calculate the statewide estimated cost and estimated crashes reduced and lives saved.
- Perform steps 1 through 3 for all of the identified countermeasures and collectively assess cost and potential crash and fatality reductions. Compare results to the intersection safety goal in the Strategic Highway Safety Plan and if necessary adjust list of countermeasures, crash thresholds, intersections to be considered for improvement, and costs to better align with the intersection goal.
- Field review the candidate intersections. The candidate intersections need to be field reviewed to determine if the low-cost countermeasures are appropriate to deploy at the intersection. In the example of the sign and marking countermeasure for a stop-controlled intersection, in addition to determining if the identified sign and marking basic countermeasures are appropriate, the intersection should also be checked to see if other crash thresholds for supplemental countermeasures, lighting, skid resistance, and speed control are met and, if so, whether additional countermeasures should be implemented.
- Tabulate the results of the field review and prepare plans to implement the countermeasures.
- Implement countermeasures, monitor and evaluate, comparing actual results to estimates.
Page last modified on September 4, 2014.