4.1 Preparing for Implementation
After selecting the appropriate engineering, education, and enforcement countermeasures, the next step is to implement them. This will involve seeking support, prioritizing the countermeasures, identifying sources of funding, and implementing pilot projects.
4.1.1 Seeking Support
Seeking support for speed-related countermeasures will requireengaging the appropriate stakeholders. Stakeholders may be anyone affected by the Speed Management Program, which could include appropriate agencies, community groups, or individuals.Enlisting stakeholder support may include holding a meeting and making a short presentation or providing a short written report to the stakeholders on the design and expected impact of the engineering countermeasure or on the plan for implementing enforcement and education campaigns to the group. When communicating with stakeholders it is essential that local practitioners understand their perspective and possible role in implementation of the program. Other methods of seeking support for a program may include hosting a public information meeting or establishing an electronic presence (e.g., Web page, Facebook page, etc.) that can be used to disseminate information and solicit feedback on the proposed countermeasures.
4.1.2 Prioritization of Countermeasures
With practically every agency being constrained by limited resources, countermeasures will need to be prioritized. Most often, the countermeasures proven to provide the most impact for the investment are given the highest priority. The following qualities of each countermeasure should be considered when establishing priorities:
- Ability to reduce crashes—Countermeasures with greater benefits should be prioritized higher. Information on the effectiveness of various engineering strategies can be found on the FHWA Crash Modification Factor (CMF) Clearinghouse Web site(47). Enforcement and educational countermeasures can be found in the NHTSA publication, Countermeasures that Work.(48)
- Potential for quick implementation—Countermeasures that can be implemented quickly (within a year) should have a higher priority. By giving greater priority to countermeasures that can be implemented quickly, an agency can ensure that the issue does not go unaddressed for several years while waiting for the implementation. Signing, pavement markings, and traditional enforcement are examples of countermeasures that can be implemented quickly.
- Benefit / cost results—Countermeasures with a greater lifecycle benefit/cost (B/C) ratio should have a higher priority, as they represent the most cost effective solutions. Calculating a B/C ratio requires information on the effectiveness and costs of the speed management strategy.
- Potential to reduce speeds—Countermeasures that are expected to result in significant reductions in vehicle speeds should have a higher priority.
For example, The Pennsylvania DOT (PennDOT) has a system to prioritize traffic calming measures in which points are assigned to locations based on criteria that include speed, volume, crashes, proximity to a school, and pedestrian facilities/generators; the greater the number of points, the greater the priority that is given to that location.(49) Table 1 outlines the ranking system used with the PennDOT program.
Table 1 . Example Project Ranking System.
| Criteria | Points | Basis for Point Assignment |
|---|---|---|
| Speed | 0 to 30 | Extent by which 85th percentile speeds exceed posted speed limit; 2 points assigned for every 1 mph |
| Volume | 0 to 25 | Average daily traffic volumes (1 point assigned for every 120 vehicles) |
| Crashes | 0 to 10 | 1 point assigned for every crash reported within past three years |
| Elementary or Middle Schools | 0 to 10 | 5 points assigned for each school crossing along the project street |
| PedestrianGenerators | 0 to 15 | 5 points assigned for each public facility (such as parks, community centers, and high schools) or commercial use that generates a significant number of pedestrians |
| Pedestrian Facilities |
0 to 10 | 5 points assigned if there are no continuous sidewalks on one side of the street; 10 points if sidewalk is missing on both sides. |
| Total Points Possible |
100 |
4.1.3 Funding
Identifying funding for each of the proposed countermeasures is essential to ensuring its implementation. There are a variety of different sources that can be used to implement the countermeasures. For engineering countermeasures, the Highway Safety Improvement Program (HSIP)(50) program is a good place to start, as it is a source of Federal funds that are typically administered by the State DOT. Because States use various methodologies to administer these funds, the practitioner should check with the State DOT on their availability.
For enforcement, education, and emergency services strategies, Section 402 funds should be considered. Section 402 funds are typically administered by each State’s GHSO.(51) Other State, local, and tribal funds may also be available for the implementation of selected countermeasures. Working with stakeholder agencies to develop speed management program can result in the pooling of resources for an effective program.
4.1.4 Planning and Using Pilot Projects
Implementing new strategies can be a challenge for an agency or community. It may be helpful to conduct a pilot project to introduce a new engineering strategy (e.g., a roundabout) or an (e.g, ASE method). Consider starting small by selecting a pilot location, or use a similar project located in a nearby location to demonstrate the effectiveness of the strategy. Effectiveness can be assessed by collecting data (e.g., speed and/or crash data) both before and after the installation of the countermeasure.
4.2 Evaluate Progress
Once a selected strategy has been implemented, it is important to evaluate its safety effectiveness. If it has been successful in reducing crashes and fatalities, then the evaluation will provide justification to potentially expand the use of the countermeasure. This section summarizes how to evaluate a speed management strategy that can be used for either one individual project or as part of a community-wide program. Each evaluation should be tailored to address specific countermeasures and conditions through analyses of the available data.
An evaluation of the impact on crash history should not be conducted until at least one year of post-installation data is available, and a minimum of three years of crash data are desirable to provide a larger sample size. The purpose of an effectiveness study is to determine if there has been a significant impact on the frequency or severity of crashes as a result of the installed countermeasure.
The recommended timeframe for a speed evaluation after a major engineering change (e.g., a new speed limit or road design element) is also one year. Waiting a full year will allow motorists to get acclimated to the new treatment and environment and will allow it to be encountered in all types of weather conditions.
The evaluation timeframe will depend on the type of countermeasure strategy pursued and the project types. The strategy must be evaluated to determine if it has been effective, partially effective, or not effective.
The simplest method for evaluating speed management strategies involves a comparison of the speed data collected before and after implementation, although it can lead to misleading results. One source of information on vehicle speeds is a full speed study conducted specifically for the purpose of evaluating speed management strategies. A formal speed study will provide the complete speed profile for the subject roadway segment and will allow a direct comparison of the observed 85th percentile speeds both before and after implementation. Additional information on how to conduct a speed study is provided in the appendix.
If an agency does not have adequate resources to execute a full speed study in conjunction with the evaluation, it may also look to some existing databases for information on vehicle speeds. For instance, the number of speeding citations issued during the before- and after-periods may be available from the files of a local law enforcement group. While the number of citations issued will not provide a complete speed profile for the subject roadway, it may still serve as a basic indicator of how successful a strategy was in mitigating a noted speeding problem. When resources other than a full speed study are used to gather speed information, one should consider any potential biases that could be introduced by those resources. For this example of using the number of citations issued, the evaluation should consider whether or not the intensity of the enforcement activities before the strategy implementation was significantly different than that afterward; i.e., did the number of citations issued increase or decrease simply because of changes in the nature of the enforcement practices.
After countermeasures have been in place for at least one year, an interim evaluation can take place. However, at least three years of after data are required for a comprehensive evaluation of implemented strategies. A before-and-after crash study can be conducted to evaluate the effectiveness of implemented strategies in improving safety when sufficient data are available. Details on creating a well-designed and executed before-and-after crash study can be found in A Guide to Developing Quality Crash ModificationFactors(45) or in the Highway Safety Manual (HSM).