Metrics

Perfect (Signal) Timing: StreetLight Adds Turning Movement Count Metrics

By September 15, 2021 No Comments

We heard you. We know it’s challenging to get turning movement counts (TMC) for every intersection you need to measure. We know because our customers have been asking us to create an easy TMC Metric that captures this critical data without going into the field.

After two months of beta testing and validations, we’re happy to announce that our TMC Metrics are now available. StreetLight InSight® users can access turning movement counts for almost any three- or four-leg intersection in the U.S. and Canada. 

Get Counts for All Intersections

Using transportation analytics for turning movement counts saves transportation engineers and planners time without putting sensor-deploying staff in harm’s way, and without relying on outdated equipment capturing data for only a few days.

StreetLight’s TMC Metrics provide counts directly from your laptop with a few clicks. Because our location-based services data sources provide counts for 365 days a year, the analyses don’t have the sample-size challenges of limited 48-hour counts.

No intersection signal? No problem. StreetLight TMC provides counts for both non-signalized and signalized intersections. You can select metrics for any hour of the day, with results down to 15-minute day part granularity to capture unique peak-hour trends. 

StreetLight’s TMC Metrics align with industry standards: Users can choose from several data visualizations including bar charts and chord diagrams. They can also export the TMC tables and intersection diagrams based on standard TMC templates.

Quick TMC for Signal Light Retiming

In Brownsville, Texas, planners at Hanson Professional Services used StreetLight Metrics to analyze the city’s 200 traffic signals, and retime 50 of them. Nada Naffakh and her team were well along with a signal modernization plan when COVID-19 upended traffic patterns, compromising data-collection plans. 

Naffakh turned to StreetLight to collect turning movement counts for “typical” months in 2019 (ones without suppressed traffic due to significant vacations or holidays). Using Metrics from those dates, the team analyzed intersection traffic volume for the smallest time increment available, and analyzed all volume for midweek days (Tuesday – Thursday). Using both visualizations and exported CSV tables, they studied the delay and capacity of all 200 traffic signals in Brownsville.

“Since obtaining accurate traffic counts was no longer feasible during COVID-19, StreetLight became the perfect tool to retroactively find traffic turning volumes.”

Nada Naffakh, Hanson Professional Services

Armed with results, the team then split the data into groups of 5-6 signal chains along each roadway, then balanced the volumes and retimed signals for each corridor. 

In addition, the team was able to project turning movements for travel expected along a new roadway extension. Existing TMC Metrics information for existing intersections were used to project redirected traffic volume. 

Naffakh’s team used O-D Metrics for their research, but now this same research can be done with TMC Metrics. Using the new product feature, analysts can access turning movement counts even faster.

Accessible TMC Means More Completed Projects

During two months of beta testing, we heard from customers who used our TMC Metrics for multiple projects, including: 

  • Measuring peak AM and PM hours for traffic impact and capacity analyses
  • Understanding inbound and outbound traffic flows for signal optimization
  • Analyzing peak hour factors for commute planning and corridor studies
  • Accessing seasonal turning movement counts for event and tourism planning
  • Determining intersection traffic activity for safety planning
  • Getting intersection traffic counts as an input for dynamic traffic assignment/microsimulation

“Being an engineer I have always used Streetlight for turning movement counts. Your new feature makes it much easier! Streetlight saves painstaking data collection in the field.”

David Pulay, PE, Akron Metropolitan Area Transportation Study

Our TMC Metrics have been tested and validated, returning a very strong R2 correlation of .95 with physical sensors. Watch our short demo video to learn how StreetLight’s TMC Metric can support your transportation work.