Appendix C: Online Collaborative Session – Executive Summary
Executive Summary
The online session involving work zone practitioners focused on the strategies used by highway agencies to determine TMP effectiveness. Practitioners discussed how best to measure effectiveness, capture useful strategies for future implementation, and include them on future projects. Practitioners were asked to comment on how effectiveness is measured in their organization and how the results of their findings are disseminated for use in current and future projects.
Defining Effectiveness
TMP effectiveness is typically defined by two overall measurable categories: mobility and safety. By analyzing crash data and its surrogates (e.g., queue length, speed through the work zone), safety benefits of the TMPs can be realized. Mobility benefits are often determined through analyses of speed, delay, travel time, or public satisfaction, among other measures. Factoring in the cost of strategies (e.g., through benefit/cost calculations) can support decision makers in choosing the most cost effectiveness treatments. Several agencies also mentioned other considerations, such as ease of use and whether project staff wants to use the strategy, as indicators of effectiveness. Some agencies include pedestrian mobility and customer satisfaction in their TMPs, but have yet to define a measurement for determining success.
Throughout the session, participants provided information on the measurements States considered important and how specific strategies were evaluated. Some practitioners shared specific metrics, while others have yet to define their measures or techniques. For example, it was apparent that public satisfaction is extremely important, but difficult to quantify.
Qualitative Evaluation
Internally, qualitative feedback is often received from field staff during construction and in post-construction meetings. Enforcement officials were considered a useful source of information by a number of session participants, as were internal staff responsible for the field review of work zones. In some cases, contract change orders were used to determine if changes to temporary traffic control were effective as participants stated that multiple charge orders to temporary traffic control could indicate the original strategies were not effective. Internal work zone inspection forms are widely used.
Externally, States often receive comments from the public related to TMP strategies. Sources include website work zone surveys, messages from social networking sites, phone surveys through customer service centers, newspaper editorials, and public meetings. Often, calls from the public can provide information about issues and can be quickly resolved in the field.
Quantitative Evaluation
To determine quantitatively the success of TMP strategies used in construction projects, data collection needs are greater than with qualitative evaluation. Data collected can include the number and severity of crashes, travel times, queue lengths, and any modifications made to temporary traffic control elements to improve safety and mobility during the project.
States collect and analyze work zone data by requiring it as part of the project, relying on law enforcement to collect through enforcement forms, having field staff travel through the work zone, or by using technology within the work zone.
According to session attendees, quality data provide hard evidence that strategies are either working or not. Not only are these data measureable and identifiable, they can also be shared among other practitioners. However, data can be difficult to get in real time and are sometimes costly to collect. In order to be truly effective, resources need to be allocated towards data collection and analysis.
Evaluation Scope/Type
With regard to the scopes/types of quantitative analyses that take place, most States responded that evaluating one strategy at multiple locations is most valuable, but this strategy was the least used among the types of evaluations mentioned during the session. Participants felt that this method would allow for the true measurement of the single strategy being tried, especially when evaluated in coordination with other strategies and compared. Project level evaluation of TMP strategies was the second favored method and had above average use. When discussing project level evaluation, States agreed that it's an effective tool for assessment and would like to see a short summary of the evaluation for use and communication.
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