Urban arterials play a major role in how people and goods move through a community. These roadways connect neighborhoods, business districts, and industrial areas, often carrying high volumes of traffic throughout the day. As demand grows, so does the need for practical solutions that improve flow without creating new safety concerns. One of the most effective ways to address both priorities is through traffic signal coordination. This article will discuss.
If you’re planning a roadway project or seeking expert opinion on signal coordination for busy corridors, working with the right engineering team matters. Contact Beaubien Engineering, LLC — located in Troy, MI, and serving states across the Midwest.
What Is Traffic Signal Coordination?
Traffic signal coordination is the process of timing traffic lights along a corridor so they work together instead of independently. When signals are properly coordinated, drivers experience fewer stops and more consistent travel speeds.
You may have heard this described as a “green wave,” where vehicles moving at a steady pace can pass through multiple intersections without stopping. While it’s not always possible to eliminate stops entirely, good coordination helps create a smoother, more predictable driving experience. Coordinated signals are designed to reduce delays and improve overall traffic flow along key corridors.
Why It Matters for Urban Arterials
Urban arterials are complex by nature. They serve many different users at once, including:
- Commuters traveling during peak hours
- Local traffic accessing businesses and neighborhoods
- Pedestrians crossing at signalized intersections
- Emergency vehicles and transit services
Without coordinated timing, these competing demands can lead to unnecessary congestion, inconsistent travel times, and increased frustration for drivers. Signal coordination helps organize traffic movement in a way that supports both efficiency and safety.
Keeping Safety Front & Center
Improving traffic flow is important, but safety is always the priority. Signal timing must account for all users of the roadway, not just vehicles moving along the main corridor.
Pedestrian Crossing Time
Signals need to provide enough time for pedestrians to cross safely, especially on wider roads or in areas with higher foot traffic.
Intersection Clearance
Proper yellow and all-red intervals help reduce the risk of collisions by giving vehicles time to clear the intersection before opposing traffic begins moving.
Reducing Conflicts
Well-coordinated signals can help limit situations where vehicles and pedestrians are competing for the same space at the same time.
Emergency Vehicle Access
Many systems include features that allow emergency vehicles to move through intersections more efficiently when needed.
Guidance from the Federal Highway Administration highlights the importance of balancing operational efficiency with safety when developing signal timing plans.
How Signal Coordination Improves Traffic Flow
There are several ways engineers approach traffic flow optimization along urban arterials.
Offset Timing
Offsets control how signals are spaced in time from one intersection to the next. Proper offsets allow traffic to move steadily along the corridor.
Time-of-Day Adjustments
Traffic patterns change throughout the day. Signal timing can be adjusted for morning, midday, and evening conditions to better match actual demand.
Progression Speed
Signals are coordinated based on a target travel speed, helping maintain consistent movement without encouraging excessive speeds.
Adaptive Signal Systems
In some cases, signals can adjust in real time using data from sensors or cameras. These systems respond to changing traffic conditions as they happen. Adaptive control can help signals respond more effectively to fluctuations in traffic volumes.
Understanding the Trade-Offs
Signal coordination is not a one-size-fits-all solution. Improving flow along a main corridor can sometimes impact other users.
Common trade-offs include:
- Longer wait times on side streets
- Increased pedestrian wait times at some intersections
- Changes in how drivers approach and move through the corridor
These factors are part of the design process. Engineers evaluate traffic data, roadway conditions, and community needs to find the right balance for each location.
How Coordination Is Implemented
Successful traffic signal coordination starts with a structured, data-driven approach.
Step 1: Data Collection
Traffic volumes, speeds, and intersection conditions are analyzed to understand how the corridor is currently operating.
Step 2: Corridor Review
Engineers look at spacing between intersections, nearby land use, and access points that may affect traffic patterns.
Step 3: Timing Development
Signal timing plans are created using modeling tools to support smoother progression.
Step 4: Field Adjustments
After implementation, timing is reviewed and refined based on real-world conditions.
Step 5: Ongoing Updates
As traffic patterns change, signal timing should be revisited to maintain performance.
Benefits of Coordinated Signals
When done well, traffic signal coordination can lead to:
- More consistent travel times
- Fewer stops along major corridors
- Smoother traffic flow
- Improved overall driving experience
Coordinated systems can improve both efficiency and overall corridor performance when properly implemented.
Looking Ahead: Evolving Traffic Technology
Traffic signal coordination continues to evolve with new technology.
- Connected vehicle systems allow communication between vehicles and signals
- Real-time data tools provide better insight into traffic patterns
- Adaptive systems allow ongoing adjustments based on current conditions
These tools offer new opportunities, but they still rely on solid engineering fundamentals to be effective.
Working With an Experienced Engineering Partner
Traffic signal coordination involves more than just adjusting signal timing. It requires an understanding of traffic behavior, roadway design, and how different users interact within a corridor.
Working with an experienced engineering firm helps provide:
- Clear, data-driven recommendations
- Solutions tailored to specific project needs
- Alignment with applicable standards and guidelines
- Ongoing support as conditions change
Look for deep industry knowledge, proven results, and a record of effective client service.
Conclusion
Traffic signal coordination is a practical way to improve how urban arterials function. By aligning signal timing with real traffic patterns, it’s possible to create a smoother flow while maintaining a strong focus on safety. Every corridor is different, which is why a thoughtful, site-specific approach is key. With the right planning and engineering support, coordinated signals can play an important role in improving both mobility and overall roadway performance.
If you need expert-backed solutions in municipal traffic engineering, transportation planning, or other areas, visit Beaubien Engineering, LLC’s services page to learn more or contact our trusted team today.