Speaking

Active Traffic Management (ATM) enables agencies to dynamically manage congestion, incidents and demand using real-time data and responsive operational strategies. For safety engineers, ATM provides an opportunity to integrate operations and geometric design to enhance both safety and reliability without major reconstruction.

This presentation examines the safety and operational benefits of strategies such as part-time shoulder use, adaptive ramp metering, variable speed limits and speed harmonization. Case studies will illustrate how these tools reduce speed differentials, smooth traffic flow and improve incident response. The presentation will also address geometric refinements that complement ATM, including understanding the difference between design speed and operating speed, studying the tradeoffs of lane and shoulder widths and context-sensitive design decisions that improve safety performance.

Specific geometric evaluations, such as a practical interpretation of horizontal stopping sight distance criteria, will be explored, including the potential to modify object height assumptions (e.g., 3.5 feet instead of 2 feet) in corridors with continuous camera detection and rapid response capabilities. The safety benefits of speed harmonization in reducing speed variance and crash risk will also be highlighted.

Finally, the presentation will identify key research needs to support effective implementation, including driver compliance with variable speed limit systems, the effectiveness of rumble strips as audible departure warnings in corridors with reduced shoulder widths and the development of meaningful measures of effectiveness for adaptive ramp metering.

By aligning ATM strategies with thoughtful geometric considerations and targeted research, agencies can optimize existing infrastructure to create safer, more reliable freeway environments.

Agencies often respond to a crash pattern with low-cost, incremental countermeasures—additional signs, channelization, turn restrictions, signal timing tweaks or spot widening. While these actions can be well intentioned and popular with the public, they may also increase speeds, shift conflict points, change crash types and severity or create behaviors that drivers ignore during off-peak conditions. The result is a repeating cycle: one "fix" creates a new problem that requires the next "fix," while the underlying intersection control and corridor context remain unchanged. 

This presentation examines multiple real-world case studies where incremental safety fixes were applied over time with limited results, delaying a more durable solution. Participants will compare those outcomes with a planning-led approach that evaluates both nodes (intersections) and links (segments between intersections), balances safety with operations and tests alternatives beyond traditional Level of Service (LOS) outputs. We will also discuss how common tools can produce misleading operational "wins" that mask rising risk and how case-study knowledge can be front-loaded into planning and public engagement. 

Roundabouts—when appropriately selected and designed—can interrupt the incremental-fix cycle by reducing severe conflicts, managing speeds and providing predictable operations and better safety outcomes for all users. The session closes with practical guidance on building internal and stakeholder support, defining performance measures that reflect both safety and capacity and selecting an intersection type that solves the problem at the location and improves the corridor as a system.