How the scorecard is built.
The INRIX Signals Scorecard summarizes signalized-intersection performance across the United States using probe-based observations from connected vehicles. This page documents the data source, sample window, Level of Service thresholds, and metric definitions that apply to every figure in the report.
Source
Metrics are based on INRIX Signal Analytics, which uses anonymized GPS pings from connected vehicles traveling through signalized intersections. Signalized intersection locations are identified using OpenStreetMap and then processed through INRIX's Signal Analytics methodology to associate observed vehicle trips with intersection movements.
The values shown on this scorecard are based on sampled vehicle crossings. They should be interpreted as probe-based performance measures, not full traffic volumes or controller-based counts.
Data window
The scorecard uses eight representative weeks from 2025, selected as two-week periods from each quarter:
- Q1: January 27 – February 9, 2025
- Q2: June 2 – June 15, 2025
- Q3: September 8 – September 21, 2025
- Q4: December 1 – December 14, 2025
These weeks were selected to create a balanced view of typical signal performance across the year while avoiding major holiday periods and other dates likely to create atypical national travel patterns.
Annual figures are calculated by rolling up performance across the full selected sample period. The underlying dataset also supports quarterly views, including the Q4–Q1 change in delay shown on the scorecard.
Level of Service
Level of Service is derived from average control delay using the Highway Capacity Manual standard for signalized intersections:
- A: less than 10 seconds
- B: 10–20 seconds
- C: 20–35 seconds
- D: 35–55 seconds
- E: 55–80 seconds
- F: greater than 80 seconds
The grade shown on any leaderboard is based on the relevant area's average control delay across observed signalized intersections.
Metric definitions
Control delay represents the estimated delay experienced by vehicles as they travel through a signalized intersection, compared with expected travel under free-flow conditions.
Arrival on green is the share of observed vehicles that arrive at and pass through a signalized movement without stopping. It is a key signal coordination metric and helps indicate how often vehicles are progressing efficiently through green indications.
Peak-hour delay is the average control delay per observed vehicle during each area's busiest observed hour within the selected scorecard data window.
Q4–Q1 change in delay compares average control delay in the fourth-quarter sample period with average control delay in the first-quarter sample period. A positive value indicates that average delay increased between Q1 and Q4, while a negative value indicates that average delay decreased.
What this scorecard does and does not show
This scorecard is intended to provide a high-level, comparable view of signal performance across states, counties, and metropolitan planning organizations. It highlights broad patterns in delay, demand, and progression using a consistent probe-based methodology.
The current dataset also supports additional views, including split failures, peak-hour Level of Service, 24×7 hour-of-day demand profiles, and county, MPO, and individual signal rollups. Arrival on green and peak-hour delay are surfaced in this scorecard; the remaining dimensions are available in the more detailed county, MPO, state, and signal-level pages.