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Traffic heat map of Rock County, Wisconsin: 748 miles of roads shaded from blue (light) to red (heavy traffic), busiest on I 39 and Milton Avenue

Rock County, Wisconsin Traffic Counts

How busy are the roads of Rock County, Wisconsin? We measure 748 road miles, divided into 11,918 segments, with multi-sourced, cross-verified mobile and sensor data. Its highways carry one of the top 5 truck shares of any county in Wisconsin. The breakdown below covers volume, trucks, congestion and driver profiles for retailers, logistics planners and engineers.
Data sourced from TrafficZoom's proprietary analytics platform.
Data current as of:
Q3 2026
Updated:
September 29, 2026
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total traffic icon

Total Traffic Volume & Performance in Rock County, Wisconsin

Traffic

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

vehicles per day4,173
Trucks

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

12.3%
Average travel time

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

34.1 min
Congestion ratio

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

12.2%
Drivers’ average age

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

47.6 yrs
Drivers’ average income

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

$78,084

A typical monitored road in Rock County, Wisconsin sees 4,173 vehicles per day, while its 748 miles of monitored roads together handle 3,531,638 vehicle-miles traveled per day (≈1.3 billion per year). At 12.3%, the truck share runs above the 10.2% across Wisconsin: about 1 in 8 vehicles.

Busier roads than 85% of counties in Wisconsin

At 4,173 vehicles per day, the average road in Rock carries somewhat more traffic than the state average of 3,802 (10% more). In total volume terms, its road network carries about 2.7% of Wisconsin's statewide total of vehicle-miles. By volume, Rock's 4,173 vehicles per day outpaces 85% of counties in Wisconsin.

Journey times run 6% higher than the state level, at 34.1 minutes on average. Its average travel time of 34.1 minutes is longer than 70% of counties in Wisconsin.

Congestion here (12.2%) closely tracks the state level.

Highway vs. Non-Highway Traffic Analysis

highway traffic icon

Highway Traffic in Rock County, Wisconsin

Trafficvehicles per day12,130
Trucks20.0%
Average travel time49.7 min
Congestion ratio25.3%
Drivers’ average age47.6 yrs
Drivers’ average income$83,731

Highways carry a significant share of travel in Rock County, Wisconsin: 44% of all vehicle-miles. The average highway carries 12,130 vehicles per day, 212% more than the average non-highway road in the same area, which carries 3,886 vehicles per day.

Yet highways are only 15% of the road network, 109 miles in 415 segments, so each mile of them is 3.0 times as busy as the average road mile.

By highway travel volume, Rock outranks 84% of counties in Wisconsin.

Higher highway truck share than 93% of counties in Wisconsin

Highway truck concentration here runs 36% higher than the state average, at 20.0%. Highways here lean toward freight, so highway access is a real asset for logistics operators.

Rock's highway truck share (20.0%) is higher than 93% of counties in Wisconsin. Rock's highway truck count is higher than 88% of counties in Wisconsin, at roughly 2,426 trucks per day.

non-highway traffic icon

Non-highway Traffic in Rock County, Wisconsin

Trafficvehicles per day3,886
Trucks6.4%
Average travel time33.6 min
Congestion ratio11.7%
Drivers’ average age47.6 yrs
Drivers’ average income$76,658

A little more than half of the driving in Rock County, Wisconsin happens on local roads: 56% of all vehicle-miles. The average non-highway road carries 3,886 vehicles per day.

Spread over 639 miles and 11,503 segments, 85% of the road network, local roads carry a lighter load per mile: 1,991,077 vehicle-miles traveled per day (≈727 million per year). About 1 in 16 vehicles on non-highway roads is a truck (6.4%).

Younger drivers than 82% of counties in Wisconsin

The concentration of trucks on non-highway roads is 68% lower than on highways.

The non-highway congestion ratio of 11.7% is in line with the state level.

63% of counties in Wisconsin see lower average driver income among trip origins than Rock. The driver population here skews younger than 82% of counties in Wisconsin.

Time-of-Day & Seasonal Patterns

peak hours icon
Peak Traffic Windows
Weekday peaks:
AM peak 7:00 AM–8:00 AM and a long afternoon plateau from 3:00 PM to 7:00 PM, with volumes reaching approximately 74% higher than the daily average.
Weekend traffic:
Weekends are somewhat quieter: volumes run about 11% below weekday levels, the usual weekend dip.
seasonal traffic icon
Seasonal Fluctuation
Busy season:
June–August is the high season, with volumes +19% versus the annual average.
Lowest month:
January is the quietest month, with volumes -21% versus the annual average - the usual winter low.

Data Finding: Hourly & Seasonal Patterns

In Rock County, Wisconsin, the peak hour concentrates about 7% of the day's traffic, and there is a strong seasonal swing of +19% in high season.

Rock County vs. Wisconsin Traffic Comparison

Of the four measures, highway truck share differs most: Rock County runs 36% above the Wisconsin average. Its truck share is also 21% above.

MetricRock CountyWisconsin averageDifference
Traffic4,1733,802+9.7%
Truck % (Total Traffic)12.3%10.2%+21.0%
Truck % (Highway)20.0%14.7%+36.1%
Avg. Travel Time34.1 min32.2 min+6.2%

How Rock County compares

Rock County against nearby counties

Rock 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 second busiest roads of the five. The same kind of road, simply more of it: traffic per road matches the areas around it while the network itself is larger.

Rock County and the 4 nearest county-level areas by centroid distance, with the Wisconsin average for scale.
AreaAverage daily trafficTruck shareDaily vehicle-milesAverage travel timeCongestion ratio
Rock County4,17312.3%3,531,63834.1 min12.2%
Winnebago County, Illinois6,4739.7%5,336,85534.9 min19.3%
Boone County, Illinois3,85013.3%1,616,46331.2 min12.0%
Green County, Wisconsin1,6897.4%672,05435.2 min8.2%
Walworth County, Wisconsin3,3349.6%2,511,83232.4 min10.6%
Wisconsin average3,80210.2%N/A32.2 min12.6%

Rock County ranked within Wisconsin

Rock County sits in the top quarter of the Wisconsin field on truck share on highways, at #5 of 58.

Rock County ranked among 72 county-level areas in Wisconsin (1 = highest); measures without data in every county rank a smaller field, down to 58.
MeasureRock CountyWisconsin rank
Traffic volume (AADT)4,173#12 of 72
Highway vehicle-miles per day1,540,561#10 of 58
Truck share on highways20.0%#5 of 58
Highway trucks per day2,426#8 of 58
Average travel time34.1 min#22 of 72
Average driver income$78,084#27 of 72
Average driver age47.6 yrs#59 of 72

Rock County ranks #5 of 58 on truck share on highways but #59 of 72 on average driver age - the two describe the same roads and are worth reading together rather than either on its own.

Busiest roads in Rock County, Wisconsin

The three busiest roads in Rock County average 34,667 vehicles a day, 8.3 times the county average of 4,173 across all its monitored roads.

I 39 is the busiest road, at 61,484 vehicles a day, 9,050 of them trucks (14.7%). That is 2.5 times the next road, Milton Avenue (24,623). It also carries the most trucks.

I 43 carries longer journeys than most roads here, with a median trip of 53.0 minutes against 34.1 county-wide.

Humes Road is busy with cars rather than freight: only 5.2% of its traffic is trucks, against 12.3% county-wide.

Ranked by daily traffic (AADT)

Cars and light vehiclesTrucks
1I 39Motorway · 61,484vehicles9,050trucks · 14.7%
Road class
Motorway
Congestion ratio
55.6%
Median trip time
49.3 min
Drivers’ median age
48.1 yrs
Drivers’ average income
$82,482

Travel on I 39's busiest stretch runs 56% over free-flow time, against 12% across the county, so expect slower peak hours.

2Milton AvenueTrunk road · 24,623vehicles1,794trucks · 7.3%
Road class
Trunk road
Median trip time
34.2 min
Drivers’ median age
46.4 yrs
Drivers’ average income
$82,664

Milton Avenue carries 5.9 times the county average at its busiest, 1,794 of them trucks (7.3%, below the county-wide 12.3%).

3Humes RoadPrimary road · 17,893vehicles939trucks · 5.2%
Road class
Primary road
Congestion ratio
22.4%
Median trip time
34.6 min
Drivers’ median age
47.9 yrs
Drivers’ average income
$82,833

Humes Road is one of the more congested roads here: trips take 22% longer than at free-flow speed, against 12% county-wide.

4WI 26Motorway · 14,267vehicles1,764trucks · 12.4%
Road class
Motorway
Congestion ratio
10.0%
Median trip time
44.0 min
Drivers’ median age
46.2 yrs
Drivers’ average income
$81,733

WI 26 peaks at 14,267 vehicles a day, 3.4 times the county average; trucks are 12.4% of it, in line with the county-wide 12.3%.

5I 43Motorway · 13,543vehicles2,479trucks · 18.3%
Road class
Motorway
Congestion ratio
12.2%
Median trip time
53.0 min
Drivers’ median age
47.8 yrs
Drivers’ average income
$80,820

I 43 carries 3.2 times the county average at its busiest, 2,479 of them trucks (18.3%, above the county-wide 12.3%).

Ranked by trucks per day

Cars and light vehiclesTrucks
1I 39Motorway · #1 by traffic61,484vehicles9,050trucks · 14.7%
2I 43Motorway · #5 by traffic13,543vehicles2,479trucks · 18.3%
3Milton AvenueTrunk road · #2 by traffic24,623vehicles1,794trucks · 7.3%
4WI 26Motorway · #4 by traffic14,267vehicles1,764trucks · 12.4%
5Avalon RoadPrimary road · 12,622vehicles1,582trucks · 12.5%
Road class
Primary road
Median trip time
33.7 min
Drivers’ median age
48.3 yrs
Drivers’ average income
$78,145

Avalon Road carries 3.0 times the county average on its busiest stretch, where the median trip lasts 33.7 minutes.

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

RockDepartment 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 Rock County

The same traffic breakdown for the areas closest to Rock County, Wisconsin.

Need segment-level traffic data?

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