1. INTRODUCTION

On September 9, 2004, the Federal Highway Administration (FHWA) amended its regulation (23 CFR Part 630) that governs traffic safety and mobility in highway and street work zones (1). The updated rule requires state departments of transportation (DOTs) to consider and establish three key components as part of an overall work zone safety and mobility program:

The required implementation of an overall, state-level work zone safety and mobility policy.
The development and implementation of standard processes and procedures to support policy implementation, including procedures for work zone impacts assessment, analyzing work zone data, training, and process reviews.
The development and implementation of procedures and transportation management plans (TMPs) to assess and manage work zone impacts on individual projects.

One of the more challenging provisions in the rule is the requirement for states to collect and analyze both safety and operational/mobility data to support the initiation, assessment, and enhancement of agency-level processes and procedures addressing work zone impacts. Specifically, states are encouraged to develop and implement systematic procedures that assess work zone impacts in project development, and states need to manage safety and mobility during project implementation (1). In addition,

“States shall use field observations, available work zone crash data, and operational information to manage work zone impacts for specific projects during implementation. States shall continually pursue improvement of work zone safety and mobility by analyzing work zone crash and operational data from multiple projects to improve state processes and procedures. States should maintain elements of the data and information resources that are necessary to support these activities” (1).

This provision in the rule does not require states to necessarily collect new data during project implementation, but to make use of whatever data they have available. However, FHWA does suggest that states may need to establish or improve processes to access, collate, and analyze that information to support safety and mobility policy activities and may need to collect additional data if limited data are currently not available (2). States are free to enhance whatever data they do collect to improve their evaluation and monitoring procedures. Obviously, the challenge facing state DOTs is to determine how to best measure and track safety and mobility impacts, and to assess how practices implemented by the DOT affect the level of impacts. Those activities need to support each agency’s policy and procedural benchmarking and evaluation in a manner consistent with FHWA requirements.

WHY MONITOR WORK ZONE PERFORMANCE?

Transportation professionals are increasingly pressed to demonstrate sound management decision-making and resource allocation. Performance management is a method to quantify and improve performance, and engage and communicate with citizens and other stakeholders (3). Overall, performance measures to gauge agency efforts are currently being used by state DOTs in the following areas:

Asset preservation
Mobility and accessibility
Operations and maintenance
Safety
Security
Economic development
Environmental
Social equity (i.e., which user groups are impacted)
Transportation delivery

Depending on the topic of interest, an agency may use “output” measures of performance that describe how much effort has been made to address a particular issue or concern, or “outcome” measures that reflect the actual effects or results experienced with respect to that issue. In fact, both types of measures are often needed to fully characterize an issue.

From the state DOT perspective, the use of work zone safety and mobility performance measures are valuable for the following reasons:

Work zone performance measures allow agencies to quantify how work zones are impacting motorists, and how actions being taken (management strategies, technologies deployed) to mitigate those impacts are or are not working. This relates directly to the intent and the requirements of 23 CFR Part 630.
Work zone performance measures assist agencies in making investment decisions, developing and improving policies, and defining program priorities. Information about the effectiveness or ineffectiveness of strategies and technologies is valuable to state DOTs when determining whether or not to include them on upcoming projects. Performance measures can also aid agencies in refining work zone policies and procedures (e.g., Is setting a specific maximum allowable delay per vehicle a useful policy objective? Do the traffic impact analysis tools being used accurately reflect what actually occurs in the field?). Finally, performance measures emphasize accountability by the agency, since what gets measured typically gets done (or is at least considered).
Work zone performance measures assist agencies in communicating with elected officials and with the public. State DOTs can use work zone performance measures to “tell their story” and ensure that everyone has the correct information about how safety and mobility is being affected by roadway construction and maintenance efforts under their jurisdiction. The story includes both what is being done and how well what is being done is working. This type of agency transparency facilitates public understanding and can improve acceptance of the impacts that do occur and builds trust that any subsequent funding will be spent wisely.

As the discussion implies, work zone performance measures can be of interest or value to a wide range of audiences. More importantly, these different audiences may need somewhat different performance measures.

WHY CONDUCT A WORK ZONE PERFORMANCE MEASURE PILOT TEST?

Although the importance of having and tracking work zone performance measures is evident, a well-defined and validated set of metrics to use in monitoring work zone performance do not currently exist. This pilot test was conducted to assist state DOTs in identifying the following:

What work zone performance measures can and should be targeted
What data they will need to collect to compute those measure
What methods exist to obtain that data.

In addition, the test was designed to generate practical guidance, lessons learned, useful tips, etc., that state DOTs could use to initiate and/or improve upon a successful work zone performance measurement program.

Although there have been a few efforts to monitor and evaluate the safety and mobility impacts of work zones to date, emphasis on systematic collection and analysis of objective data to develop quantitative measures of work zone performance is still lacking. Therefore, a pilot test effort to develop and utilize quantitative measures at several real-world work zone projects was undertaken.

previous | next