When Peak Traffic Fades,
What Happens to Speed?
When peak-hour congestion clears, speeds can rise sharply on Philadelphia's roads. This tool maps predicted speeding risk for monitored road segments across all four time periods: morning peak, midday off-peak, evening peak, and night off-peak. It also lets planners simulate how road design changes would shift that risk.
How the Model Works
Speed observations
DVRPC sensors record the share of vehicles exceeding the speed limit each hour on monitored segments.
Feature engineering
Road geometry, classification, environment, traffic volume, crash history, and time-of-day are compiled per segment.
Random Forest model
A ranger-based Random Forest (R² = 0.92, MAE = 4.2%) learns the relationship between road features and speeding rate.
Intervention prediction
Select pre-computed intervention scenarios in the panel to see the model's estimated change in off-peak speeding for any segment.
What This Tool Does
Interactive Risk Map
Every Philadelphia road segment colored by predicted off-peak speeding risk. Toggle between four time periods and switch views between predicted speeding, road class, speed limit, or number of lanes.
Explore the Map →Intervention Simulator
Click any segment to open its detail panel. Select intervention types — lane diet, bike lanes, traffic calming, parking changes — and compare the model's predicted speeding before and after each scenario.
Try an Intervention →Segment Data Table
Browse and sort all road segments by predicted speeding rate, crash rate, KSI rate, road class, and physical characteristics to prioritize interventions.
View Table →Methodology & Data
Full documentation of the Random Forest model, predictors, training data, validation metrics, and limitations.
Read More →Speeding Risk Categories
Fewer than 1 in 10 vehicles exceeds the speed limit. Typical of local residential streets with traffic calming.
Consistent off-peak speeding. Often found on collector roads with moderate volume and no calming.
Significant speeding risk. Common on minor and major arterials late at night.
More than 1 in 3 vehicles exceeds the limit. Associated with wide, multi-lane, high-speed corridors like Roosevelt Blvd.