Introduction
The TMC Analysis (Turning Movement Counts) module within iNode is purpose-built for intersection-level analysis. It uses aggregated vehicle trip data to quantify how many vehicles are making specific turning movements through an intersection, delivering turning movement counts that support planning, operational review, and engineering assessment.
Metrics and Use Case
Metric
The TMC Analysis module measures Turning Movement Count: the estimated number of vehicles completing each approach (e.g., left turn, right turn, through) from a given approaches (e.g., northbound, southbound) at a selected intersection for a defined date and time period.
Use Case
Turning movement counts support a range of intersection-focused analyses, including:
- Evaluating peak-hour demand by approach
- Supporting signal timing reviews and retiming studies
- Assessing intersection capacity and level of service
- Identifying imbalance between opposing or competing approaches
- Screening locations for geometric improvements (e.g., added turn lanes)
- Supporting traffic impact studies and development applications
- Providing historical count context where field counts are unavailable
The TMC Analysis module complements traditional field counts by offering scalable, time-filterable turning movement counts without requiring on-site data collection.
Key Components and Workflows
The TMC Analysis module makes it easier to analyze various metrics through a guided workflow, ensuring flexibility while keeping studies easy to set up:
- Create a new study: Define your study parameters, including vehicle types and distance units, to align the analysis with your objectives.
- Movement Selection: Select the movements (e.g., northbound, southbound) and approaches (e.g., left turn, right turn, through) to include in your study.
- Trip condition selection: Filter by when trips start, end, or both, allowing targeted analysis of specific time periods.
- Date range and time set selection: Define precise ranges to capture short-term events or long-term patterns.
- Map selection: Visualize your road networks through Orbis or Genenis.
- Study confirmation: Review your study parameters, including expected sample size and credit usage, before finalizing.
- Result delivery: Access comprehensive result pages with clear summaries, visualizations, and data exports for deeper analysis.
Data Sources
At its core, iNode’s TMC Analysis module is powered by high-resolution GPS probe data. Data is collected from:
- Connected GPS devices
- Embedded vehicle telematics systems
- GPS-enabled mobile phones
This data is continuously archived, creating a robust historical traffic database. The result is a rich, scalable foundation for travel time, speed and volume studies that combine real-time insights with long-term context, making the TMC Analysis module a key component of iNode - an advanced traffic data analytics platform.
Data Availability and Updates
TMC Analysis data is continuously updated as it moves through iNode’s processing pipeline, where it is cleaned, aggregated, and validated to ensure consistent, reliable results. Data is typically available with a one-day lag, meaning studies can be submitted for as recent as yesterday or today; however, to achieve optimal sample sizes and the highest data quality, we recommend waiting up to 72 hours before submitting a study, as some GPS data providers deliver data with delays beyond 24 hours.