Understanding Turning Movement Counts: Basics, Process & Importance
Turning Movement Counts (TMC) are one of the most fundamental traffic engineering studies used to understand how vehicles move through intersections. These counts record the number of vehicles turning left, right, or going straight during specific time intervals. The data collected from TMCs plays a vital role in improving traffic signal timing, reducing congestion, and planning infrastructure upgrades.
What Are Turning Movement Counts?
Turning Movement Counts are traffic studies conducted at intersections to determine how many vehicles are performing specific maneuvers:
Left Turns
Right Turns
Through Movements
These counts are usually taken during peak traffic hours—morning (AM), midday (MD), and evening (PM)—to evaluate intersection performance during high-demand periods. Depending on the project needs, TMCs can be done over 1-hour, 2-hour, or full-day intervals.
How Are TMCs Conducted?
TMCs can be performed using several methods:
1. Manual Counts
Observers are stationed at intersections and tally vehicle movements using handheld devices or tally sheets. This method is precise when human judgment is needed—for example, classifying unusual vehicle behavior.
2. Video-Based Counts
High-definition cameras are installed to record traffic flow, and the footage is later analyzed either manually or using specialized software. This method ensures data can be verified post-collection and provides a permanent record.
3. Software-Assisted Counts
Modern traffic video analysis software can identify and classify vehicles automatically. This speeds up processing and ensures higher consistency across long durations.
To learn more about our video-based and manual TMC services, visit our Traffic Turning Movement Counts Analysis page.
Importance of TMCs in Traffic Engineering
Accurate Turning Movement Counts support critical traffic decisions. Here’s how:
🟢 Traffic Signal Timing Optimization
Traffic engineers use TMCs to adjust signal phases and timings, reducing wait times and improving overall flow.
🟢 Intersection Design
Data from TMCs helps planners determine if an intersection needs redesign—like adding turn lanes or roundabouts.
🟢 Road Safety Improvements
High volumes of turning traffic can lead to conflict points. TMC data reveals these hotspots so that countermeasures like signage or signal changes can be applied.
🟢 Traffic Impact Assessments (TIA)
For new developments, TMCs form a critical component of TIA studies, showing how added traffic will affect existing intersections.
🟢 Project Prioritization
Local governments and urban planners rely on TMC data to decide which intersections need urgent upgrades and funding.
Vehicle Classification in TMC Studies
Turning movements are not just about the number of vehicles but also their type. Many TMC studies classify vehicles into categories:
Cars
Light Commercial Vehicles (LCVs)
Buses
Trucks
Two-Wheelers
Three-Wheelers
Non-Motorized Vehicles (NMVs)
This level of detail enhances planning accuracy, especially for cities dealing with mixed traffic patterns.
When Should You Conduct a TMC?
TMC studies are usually conducted when:
Upgrading intersections or signal timings
Planning new residential or commercial developments
Evaluating accident-prone areas
Assessing road network efficiency
They are essential for urban planning, traffic calming, smart city projects, and corridor-level improvements.
Why Choose Professional TMC Services?
While TMC might seem straightforward, ensuring accuracy across complex intersections, multiple vehicle classes, and peak traffic volumes demands expertise.
At Traffic Data Count, we combine manual precision with high-end video technology to deliver:
Detailed reports
Peak hour analysis
Classified vehicle movement data
Exportable Excel summaries
Integration-ready formats for traffic modeling tools
Conclusion
Turning Movement Counts are not just a set of numbers—they are foundational to better traffic flow, safer roads, and smarter urban design. Whether you’re a traffic engineer, planner, or developer, TMCs offer the clarity needed for confident decision-making.
For high-accuracy TMC surveys tailored to your project, explore our dedicated service page:
👉 Traffic Turning Movement Counts Analysis
