This page delivers traffic analytics for St. Clair County, Illinois. Our metrics are calculated with multi-sourced, cross-verified data from real-world mobile and sensor networks, and averaged for St. Clair County, Illinois among 740 road miles divided in 16,476 segments. Our metrics go beyond simple volume counts to provide actionable insights on traffic intensity, congestion, commercial vehicle flow, and network performance with highest possible granularity (average segment length is 237 ft). Whether you are evaluating a new retail location, planning logistics routes, or assessing infrastructure needs, this data helps you move from assumptions to certainty.
Data sourced from TrafficZoom's proprietary analytics platform.
The average number of vehicles that travel each day over any road in the road network.
7,262
Trucks
Trucks
The percentage of the total traffic volume composed of heavy vehicles.
9.1%
Average travel time
Average travel time
The average time of travel averaged among all vehicles traveling on the road network.
31.9 min
Congestion ratio
Congestion ratio
The rate at which the actual travel time exceeds free-flow travel time, averaged among all roads in the network.
17.6%
Drivers’ average age
Drivers’ average age
Average age of residents in the geographic areas where the vehicle trips originated.
46.4 yrs
Drivers’ average income
Drivers’ average income
Average income of residents in the geographic areas where the vehicle trips originated.
$90,277
Our data indicates an estimated average traffic volume of 7,262 vehicles per day in St. Clair County, Illinois that results in 6,124,421 vehicle-miles traveled per day (≈2.2 billion per year). The traffic stream is comprised of an average of 1 truck for every 11 vehicles. Typical time spent behind the wheel per trip is 31.9 minutes, which already accounts for delays at signals, intersections, and congestion.
Analytical insight
When compared to the Illinois state averages: At 7,262 vehicles per day, the average monitored road in St. Clair carries 14% less traffic than the state average of 8,480 vehicles per day - a critical factor for logistics and site planning. Across the whole network that adds up to 6,124,421 vehicle-miles traveled per day (≈2.2 billion per year), roughly 2.6% of Illinois's statewide total. At 31.9 minutes, the average travel time is 7% lower than the state level. At 15% lower than the state level, the 17.6% congestion ratio signals smoother traffic flow - crucial for traffic control improvement and logistics planning. 93% of counties in Illinois see less traffic than St. Clair's 7,262 vehicles per day. Its average travel time of 31.9 minutes is longer than 22% of counties in Illinois.
Highway vs. Non-Highway Traffic Analysis
Highway Traffic
Traffic
Traffic
The average number of vehicles that travel each day over any road in the road network.
18,003
Trucks
Trucks
The percentage of the total traffic volume composed of heavy vehicles.
14.1%
Average travel time
Average travel time
The average time of travel averaged among all vehicles traveling on the road network.
39.1 min
Congestion ratio
Congestion ratio
The rate at which the actual travel time exceeds free-flow travel time, averaged among all roads in the network.
33.8%
Drivers’ average age
Drivers’ average age
Average age of residents in the geographic areas where the vehicle trips originated.
46.2 yrs
Drivers’ average income
Drivers’ average income
Average income of residents in the geographic areas where the vehicle trips originated.
$88,163
A significant volume of traffic in St. Clair County, Illinois utilizes the highway network. The average highway carries 18,003 vehicles per day, 165% more than the average non-highway road in the same area, which carries 6,791 vehicles per day. That average covers 156 highway road miles divided in 692 segments (average segment length 1,191 ft), together carrying 2,765,567 vehicle-miles traveled per day (≈1.0 billion per year). By highway travel volume, St. Clair outranks 94% of counties in Illinois. Trucks constitute 14.1% of highway traffic.
Analytical insight
At 14.1%, highway truck share is 19% lower than the state average, marking St. Clair as a primarily local traffic hub - underscoring the importance of local access for logistics operators. St. Clair's highway truck share (14.1%) is higher than 27% of counties in Illinois. 60% of counties in Illinois see fewer highway trucks per day than St. Clair's roughly 2,531.
Non-highway traffic
Traffic
Traffic
The average number of vehicles that travel each day over any road in the road network.
6,791
Trucks
Trucks
The percentage of the total traffic volume composed of heavy vehicles.
5.0%
Average travel time
Average travel time
The average time of travel averaged among all vehicles traveling on the road network.
31.6 min
Congestion ratio
Congestion ratio
The rate at which the actual travel time exceeds free-flow travel time, averaged among all roads in the network.
16.9%
Drivers’ average age
Drivers’ average age
Average age of residents in the geographic areas where the vehicle trips originated.
46.5 yrs
Drivers’ average income
Drivers’ average income
Average income of residents in the geographic areas where the vehicle trips originated.
$91,219
The non-highway road network in St. Clair County, Illinois supports a substantial volume of traffic. The average non-highway road carries 6,791 vehicles per day, 62% less than the average highway in the same area, which carries 18,003 vehicles per day. That average covers 584 non-highway road miles divided in 15,784 segments (average segment length 195 ft), together carrying 3,358,854 vehicle-miles traveled per day (≈1.2 billion per year). Trucks constitute 5.0% of non-highway traffic.
Analytical insight
The concentration of trucks on non-highway roads is 64% lower than on highways. At 18% lower than the state level, the non-highway congestion ratio of 16.9% signals easier movement on local roads. 22% of counties in Illinois see shorter overall travel times than St. Clair. Trip origins here have higher average income than 86% of counties in Illinois. 13% of counties in Illinois have a younger driver population than St. Clair.
Time-of-Day & Seasonal Patterns
Peak Traffic Windows
Weekday peaks:
AM peak 7:00 AM–9:00 AM and PM peak 3:00 PM–7:00 PM, with volumes reaching approximately 76% higher than the daily average.
Weekend traffic:
Weekend volumes run about 31% below weekday levels.
Seasonal Fluctuation
Busy season:
August–October is the high season, with volumes +4% versus the annual average.
Lowest month:
July is the quietest month, with volumes -12% versus the annual average.
Analytical insight
In St. Clair County, Illinois, the peak hour concentrates about 7% of the day's traffic, and seasonal swing is mild at +4% in high season.
Traffic Flow Profile Comparison
Metric
St. Clair
Illinois
Average
Difference
Traffic
7,262
8,480
-14.4%
Truck % (Total Traffic)
9.1%
10.2%
-10.4%
Truck % (Highway)
14.1%
17.3%
-18.9%
Avg. Travel Time
31.9 min
34.1 min
-6.6%
Frequently Asked Questions
The average daily traffic volume is calculated at 7,262 vehicles per day, providing a baseline for daily operations and site assessment.
St. Clair's average travel time of 31.9 minutes is longer than 22% of counties in Illinois.
Weekday peaks occur between 7:00 AM and 9:00 AM in the morning and between 3:00 PM and 7:00 PM in the evening - about 76% above the daily average.
The average travel time for drivers is 31.9 minutes, offering a standard metric for commute and delivery route planning.
Approximately 39% of highway traffic and 9% of non-highway traffic consists of vehicles whose trip originates outside St. Clair County, Illinois. This indicates that a portion of highway traffic is regional pass-through, while local roads are more representative of resident and commuter activity.
Traffic volumes are typically 4% higher during August–October. Volumes drop to their lowest levels in July, averaging 6,425 vehicles per day - a 12% decrease from the annual average.
Trucks account for approximately 9.1% of the total traffic mix across all road types, with a significantly higher concentration of 14.1% on highways.
Drivers on St. Clair roads have a median age of 46 years, and the median household income of the neighborhoods trips originate from averages $90,277 - useful context for retail siting and customer profiling.
Data Sources & Methodology
The data presented on this page is derived from TrafficZoom's proprietary analytics platform, which aggregates and normalizes information from multiple sources, including:
Mobile device location data (anonymized and aggregated)
