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Traffic heat map of St. Clair County, Alabama: 461 miles of roads shaded from blue (light) to red (heavy traffic), busiest on I 20 and I 59

St. Clair County, Alabama Traffic Counts

TrafficZoom tracks traffic on 461 road miles in St. Clair County, Alabama, divided into 6,295 segments averaging 387 ft. Its highways rank among the top 3 counties in Alabama for trucks per day. Built from cross-verified mobile and road-sensor data, these counts help you size up a retail site, plan logistics routes or assess infrastructure needs.
Data sourced from TrafficZoom's proprietary analytics platform.
Data current as of:
Q3 2026
Updated:
September 29, 2026
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Total Traffic Volume & Performance in St. Clair County, Alabama

Traffic

The average number of vehicles that travel each day over any road in the road network.

vehicles per day4,995
Trucks

The percentage of the total traffic volume composed of heavy vehicles.

14.9%
Average travel time

The average time of travel averaged among all vehicles traveling on the road network.

29.5 min
Congestion ratio

The rate at which the actual travel time exceeds free-flow travel time, averaged among all roads in the network.

13.3%
Drivers’ average age

Average age of residents in the geographic areas where the vehicle trips originated.

47.4 yrs
Drivers’ average income

Average income of residents in the geographic areas where the vehicle trips originated.

$79,371

A typical monitored road in St. Clair County, Alabama sees 4,995 vehicles per day, while its 461 miles of monitored roads together handle 2,968,588 vehicle-miles traveled per day (≈1.1 billion per year). At 14.9%, the truck share runs above the 10.6% across Alabama: about 1 in 7 vehicles.

Shorter trips than 97% of counties in Alabama

St. Clair sees 16% lower average daily traffic volume than the state average (4,995 vehicles per day against 5,932), suggesting less demand on each road - a critical factor for logistics and site planning. In total volume terms, its road network carries about 2.1% of Alabama's statewide total of vehicle-miles. 67% of counties in Alabama see less traffic than St. Clair's 4,995 vehicles per day.

Journey times run 7% lower than the state level, at 29.5 minutes on average. On travel time, St. Clair runs shorter than 97% of counties in Alabama.

Congestion is somewhat lower than the state level, at a ratio of 13.3% (14% lower) - crucial for traffic control improvement and logistics planning.

Highway vs. Non-Highway Traffic Analysis

highway traffic icon

Highway Traffic in St. Clair County, Alabama

Trafficvehicles per day18,227
Trucks20.6%
Average travel time48.0 min
Congestion ratio23.8%
Drivers’ average age46.2 yrs
Drivers’ average income$78,539

Highways carry more than half of all travel in St. Clair County, Alabama (59% of vehicle-miles). The average highway carries 18,227 vehicles per day, 283% more than the average non-highway road in the same area, which carries 4,753 vehicles per day.

With 22% of the road miles (103 miles in 113 segments), highways punch above their length, carrying 1,746,050 vehicle-miles traveled per day (≈637 million per year).

85% of counties in Alabama move less traffic on their highways.

More highway trucks than 98% of counties in Alabama

The concentration of trucks on highways (20.6%) is 39% higher than the state average for similar road classifications. Highways here lean toward freight, so highway access is a real asset for logistics operators.

83% of counties in Alabama see a lower highway truck share than St. Clair's 20.6%. By raw truck volume, St. Clair carries more highway trucks than 98% of counties in Alabama.

non-highway traffic icon

Non-highway Traffic in St. Clair County, Alabama

Trafficvehicles per day4,753
Trucks6.7%
Average travel time29.2 min
Congestion ratio13.1%
Drivers’ average age47.8 yrs
Drivers’ average income$79,952

A significant share of driving in St. Clair County, Alabama, 41% of vehicle-miles, happens on local roads. A typical local road sees 4,753 vehicles per day.

Spread over 358 miles and 6,182 segments, 78% of the road network, local roads carry a lighter load per mile: 1,222,538 vehicle-miles traveled per day (≈446 million per year). About 1 in 15 vehicles on non-highway roads is a truck (6.7%).

Drivers from higher-income areas than 94% of counties in Alabama

Non-highway roads carry a truck concentration that's 67% lower than the highway network.

Non-highway congestion (13.1%) runs slightly lower than the state level (11% lower).

94% of counties in Alabama see lower average driver income among trip origins than St. Clair. 65% of counties in Alabama have an older driver population than St. Clair.

Time-of-Day & Seasonal Patterns

Data Finding: Hourly & Seasonal Patterns

In St. Clair County, Alabama, the peak hour concentrates about 7% of the day's traffic.

St. Clair County vs. Alabama Traffic Comparison

The truck share sets St. Clair County apart: 40% above the Alabama average. Its highway truck share is also 39% above.

MetricSt. Clair CountyAlabama averageDifference
Traffic4,9955,932-15.8%
Truck % (Total Traffic)14.9%10.6%+40.0%
Truck % (Highway)20.6%14.8%+38.9%
Avg. Travel Time29.5 min31.8 min-7.3%

How St. Clair County compares

St. Clair County against nearby counties

St. Clair County tracks the 4 areas around it closely - no measure in this table sets it far apart from the areas immediately next to it, though it has the fourth busiest roads of the five. Traffic volume here matches the areas around it, but more of that traffic is trucks - a difference in what routes through, not in how much.

St. Clair County and the 4 nearest county-level areas by centroid distance, with the Alabama average for scale.
AreaAverage daily trafficTruck shareDaily vehicle-milesAverage travel timeCongestion ratio
St. Clair County4,99514.9%2,968,58829.5 min13.3%
Talladega County, Alabama4,18414.7%2,440,52735.8 min10.6%
Blount County, Alabama5,08410.4%1,486,17631.4 min12.2%
Calhoun County, Alabama5,54111.0%2,988,92431.9 min14.2%
Etowah County, Alabama6,12210.5%2,556,64536.4 min15.8%
Alabama average5,93210.6%N/A31.8 min15.5%

St. Clair County ranked within Alabama

St. Clair County sits in Alabama's top three on highway truck volume.

St. Clair County ranked among 67 county-level areas in Alabama (1 = highest); measures without data in every county rank a smaller field, down to 60.
MeasureSt. Clair CountyAlabama rank
Traffic volume (AADT)4,995#23 of 67
Highway vehicle-miles per day1,746,050#10 of 60
Truck share on highways20.6%#11 of 60
Highway trucks per day3,749#2 of 60
Average travel time29.5 min#65 of 67
Average driver income$79,371#5 of 67
Average driver age47.4 yrs#44 of 67

St. Clair County ranks #2 of 60 on highway truck volume but #65 of 67 on average travel time - the two describe the same roads and are worth reading together rather than either on its own.

Busiest roads in St. Clair County, Alabama

The three busiest roads in St. Clair County average 32,438 vehicles a day, 6.5 times the county average of 4,995 across all its monitored roads.

I 20 is the busiest road, at 49,084 vehicles a day, 11,098 of them trucks (22.6%). No other road comes close: I 59, in second place, carries 25,031. It tops the truck ranking too, with the most trucks.

I 20 carries longer journeys than most roads here, with a median trip of 47.1 minutes against 29.5 county-wide.

Few trucks use Martin Street: 3.8% of its traffic, under half the county's 14.9%.

Freight stands out on I 20: trucks are 22.6% of the traffic there, against 14.9% county-wide.

Ranked by daily traffic (AADT)

Cars and light vehiclesTrucks
1I 20Motorway · 49,084vehicles11,098trucks · 22.6%
Road class
Motorway
Congestion ratio
28.0%
Median trip time
47.1 min
Drivers’ median age
45.7 yrs
Drivers’ average income
$79,420

At 9.8 times the county average, I 20 draws drivers from neighborhoods averaging $79,420 in household income.

2I 59Motorway · 25,031vehicles4,161trucks · 16.6%
Road class
Motorway
Congestion ratio
18.9%
Median trip time
45.2 min
Drivers’ median age
47.1 yrs
Drivers’ average income
$79,663

Drivers on I 59 are on long journeys, a median 45.2 minutes against 29.5 county-wide: a through route more than a local street.

3Martin StreetPrimary road · 23,200vehicles882trucks · 3.8%
Road class
Primary road
Congestion ratio
29.6%
Median trip time
29.8 min
Drivers’ median age
48.4 yrs
Drivers’ average income
$76,262

Delays build on Martin Street: its congestion ratio of 30% over free-flow time is well above the county's 13%.

4Moody ParkwayPrimary road · 20,724vehicles1,014trucks · 4.9%
Road class
Primary road
Congestion ratio
37.9%
Median trip time
28.1 min
Drivers’ median age
47.0 yrs
Drivers’ average income
$87,170

Travel on Moody Parkway's busiest stretch runs 38% over free-flow time, against 13% across the county, so expect slower peak hours.

5Heart of Dixie HighwayPrimary road · 20,402vehicles1,004trucks · 4.9%
Road class
Primary road
Congestion ratio
26.3%
Median trip time
31.6 min
Drivers’ median age
48.6 yrs
Drivers’ average income
$76,851

On its busiest stretch, Heart of Dixie Highway carries 4.1 times the county average; trucks are 4.9% of it, below the county-wide 14.9%.

Ranked by trucks per day

Cars and light vehiclesTrucks
1I 20Motorway · #1 by traffic49,084vehicles11,098trucks · 22.6%
2I 59Motorway · #2 by traffic25,031vehicles4,161trucks · 16.6%
3Moody ParkwayPrimary road · #4 by traffic20,724vehicles1,014trucks · 4.9%
4Heart of Dixie HighwayPrimary road · #5 by traffic20,402vehicles1,004trucks · 4.9%
5Martin StreetPrimary road · #3 by traffic23,200vehicles882trucks · 3.8%
How to read these road counts
  • The first number is AADT, annual average daily traffic: the vehicles passing a point on an average day, both directions combined and trucks included. On a divided highway both carriageways are added together.
  • Traffic changes along a road, with more near interchanges and towns and less in open country. Every figure for a road describes its busiest stretch in the county, so the two rankings show the same numbers for the same road.
  • The second number is the trucks on that stretch, a part of its AADT. The bar splits the AADT into cars and light vehicles (blue) and trucks (amber).
  • See segment-level AADT for any road on TrafficZoom.

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)

Road sensor networks and traffic counters

Historical traffic pattern databases

Public traffic count programs published by the

St. ClairDepartment of Transportation

Demographic Baseline for O-D Modeling

U.S. Census Bureau
All metrics represent estimates based on statistical modeling and are intended for strategic planning purposes.
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Data current as of:
Q3 2026

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Counties near St. Clair County

The same traffic breakdown for the areas closest to St. Clair County, Alabama.

Need segment-level traffic data?

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