The whole analysed freeway network at a glance: each segment colored by its typical weekday 5–6 PM speed relative to free flow (median of the year's weekday speeds in that hour), with the region's top-20 freeway bottlenecks (Regional Congestion Report ranking) marked. Use the other tabs to change the hour, the measure or the direction, or to look inside a corridor.
Top-20 freeway bottlenecks (regional report ranking)
The freeway bottlenecks ranked in the Regional Congestion Report (AADT-weighted severity index), at their peak segment. Click a row to see that freeway's time–space diagram.
Speeds are compared with each segment's own free-flow speed and grouped into fixed classes — the same breaks every run and every year, so maps and charts can be compared over time. The 70% break is the analysis's congestion threshold. The chart shows how many directional freeway miles fall in each class in each hour of a typical day. Click a bar to open that hour on the Time of Day map.
Typical conditions hour by hour. Drag the slider, use the presets, or press Play to watch congestion form and clear across the day. Weekdays and weekends are summarised separately (median speed in each hour), so holidays and unusual days don't dilute the peak.
How much delay, not just how slow. Color shows the average day's estimated vehicle-hours of delay per mile in the selected hour (directional NPMRDS AADT × hourly distribution × excess travel time); line width shows directional traffic volume. A busy road with a moderate speed drop can carry more delay than a quiet road with a severe one.
Segments with the most delay in this hour
Each direction of travel is drawn on its own side of the road. Pick one direction to see it alone — inbound and outbound peaks often differ sharply. The table lists sections whose two directions differ most in the selected hour.
Sections with the largest difference between directions
A time–space diagram shows where and when congestion forms along one section: distance along the road runs left to right in the direction of travel, hour of day runs top to bottom. A recurring bottleneck is a dark patch that starts at a fixed point and grows to the left (upstream) as the queue builds; where it ends is when the queue clears. Hover a cell for its cross street and hour.
Everything for one segment. Search by road or cross street, or click any segment on a map in the other tabs.
No segment selected yet.
Color = speed vs free flow
Height = delay per mile
Tallest walls this hour
Compare hours and roads directly. One player drives all three views: the road race shows which sections carry the most delay in each hour (one fixed scale for every hour, so bar lengths compare across the day); the heatmap shows every hour of the worst sections at once; the small maps show the whole network once per hour, side by side. Click any small map or heatmap column to jump to that hour.
Road race — most delay in this hour
Each bar is one section and direction. Delay per mile (default) ranks how intense the delay is, the same basis as the corridor rank, so long and short sections compare fairly; Total delay ranks how much delay a section carries in all, which favours long sections. Length = the chosen measure in this hour on a typical day, color = typical speed vs free flow. Click a bar for its time–space diagram.