The Road Safety Management Process

The Road Safety Management Process

Use a connected sequence of decisions

The Highway Safety Manual Part B organizes roadway safety management into six steps: network screening, diagnosis, countermeasure selection, economic appraisal, project prioritization, and safety effectiveness evaluation. Each step answers a different question and supplies information for the next. The process is iterative; evaluation and new data feed future screening and selection.

The sequence prevents a common error: choosing a familiar treatment before defining the problem. A list of high-crash locations is not a diagnosis, and a favorable CMF is not a completed investment decision. A sound program connects the evidence from problem identification through implementation and learning. FHWA Road Safety Fundamentals, Unit 4

Step 1: Network screening

Screening identifies locations or risk profiles for further investigation. Establish the focus, facility population, performance measure, and method. Use suitable crash, roadway, and exposure data, with attention to quality and comparability. A total-crash objective can produce a different priority list from a fatal-and-serious-injury objective.

Site-specific screening looks for unusual or consequential performance at particular locations. Systemic screening identifies features associated with severe outcomes across a network, even where events are dispersed. They can complement each other. Screening ranks investigative needs; it does not prove a site's cause or the amount of benefit available from a treatment.

Step 2: Diagnosis

Diagnosis examines patterns and contributing mechanisms. Review coded data, narratives, collision diagrams, road conditions, speeds, field observations, and affected users. Confirm locations and consider relevant time, weather, and operation. A directional pattern can suggest a sight or gap problem, but alternative explanations should remain open until tested.

Use a multidisciplinary team where the issue spans roles. Maintenance staff may know a recurring drainage condition; enforcement may know a behavioral pattern; transit staff may know crossing demand; health partners may clarify injuries. The diagnostic output should describe the supported pattern, plausible mechanisms, and uncertainty, rather than merely restating “many crashes.”

Step 3: Select countermeasures

Choose candidates that address the diagnosed mechanism. Locate applicable infrastructure and behavioral evidence, then consider users, authority, feasibility, maintenance, and interactions. A friction treatment may fit a friction-demand problem, while clearer guidance may fit late recognition. Several layers may be appropriate when mechanisms interact.

A treatment's name or inclusion on a proven list does not make it suitable everywhere. Match CMFs to type, severity, facility, and conditions. Review adverse effects and users outside the initial analysis. Document alternatives instead of presenting one preferred treatment as the only possible response before appraisal.

Step 4: Economic appraisal

Estimate expected outcome changes, costs, service life, maintenance, and relevant benefits under consistent assumptions. Discount future costs and benefits using the applicable analysis guidance. Distinguish person and crash units and avoid double counting. A benefit-cost ratio and net present value describe different aspects of the result.

Include nonmonetized effects such as accessibility, noise, environmental impacts, community connectivity, and emergency access. Economic analysis supports a choice; it does not remove statutory obligations or resolve every social trade-off. Sensitivity analysis helps show whether uncertainty in effect, cost, or life changes the recommendation.

Step 5: Prioritize projects

For mutually exclusive alternatives at one site, compare incremental benefits and costs or consistent net benefits rather than selecting only the highest individual ratio. For a network program, consider budget, project dependencies, deliverability, risk distribution, and the adopted goals. A greedy ratio ranking is not guaranteed to maximize benefits for indivisible projects.

Assign responsibilities, funding, milestones, and maintenance. An economically favorable concept can still be impractical without authority, right-of-way, staff, or support. Prioritization should explain the selected program and the deferred alternatives, including the assumptions and constraints that led to the choice.

Step 6: Evaluate safety effectiveness

Plan the evaluation before implementation so baseline and treatment data are preserved. Define intended outcomes, exposure, comparison approach, observation periods, and adverse effects. Before-after and cross-sectional methods have different strengths and limitations. Naive changes can reflect RTM, traffic, reporting, weather, or broader trends rather than only treatment.

Evaluation can inform local practice, future project estimates, and research. It does not automatically recalibrate every SPF or make a site permanently exempt from screening. Maintain documentation and distinguish package effects from individual component effects when several interventions were installed together.

Apply the process through the project lifecycle

Safety analysis can support planning, alternatives, preliminary and final design, construction transitions, operation, and maintenance. Earlier comparison can influence fundamental choices before they become difficult to change. A pre-opening review can identify information or visibility problems in the built facility. Operational monitoring can reveal issues that were not apparent in plans.

The process should fit the scale and question. A low-cost maintenance action need not become an unnecessarily elaborate capital study, but should still connect a documented problem to a reasonable response and follow-up. A major corridor change needs broader analysis and coordination.

The management cycle

• Screen the network and diagnose contributing mechanisms.
• Select countermeasures and appraise alternatives.
• Prioritize feasible projects and evaluate their effects.
• Use findings to improve the next cycle.

Work a coherent example

A county screens rural curves for severe departures. Diagnosis at a priority group finds wet-weather patterns, high approach speeds, and limited recovery space. The team considers surface treatment, guidance, speed measures, and roadside options. Appraisal estimates type-specific benefits and costs, including maintenance. Prioritization selects a feasible package and a schedule.

Before installation, the county defines evaluation periods, exposure, comparison models, and implementation records. Later results are reviewed with the limitations stated. If departures fall but nearby conflicts rise, the program revisits the diagnosis and package. This is a management loop that learns, rather than a one-time declaration that the original treatment solved safety permanently.