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Traffic heat map of Williamson County, Texas: 1,411 miles of roads shaded from blue (light) to red (heavy traffic), busiest on Purple Heart Trail

Williamson County, Texas Traffic Counts

Traffic analytics for Williamson County, Texas, calculated from real-world mobile and sensor networks on 26,567 road segments (1,411 road miles, about 280 ft each). Its drivers come from neighborhoods among the top 5 counties in Texas for household income. Use the figures below to move from assumptions to certainty on retail locations, logistics and road planning.
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 Williamson County, Texas

Traffic

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

vehicles per day8,688
Trucks

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

7.7%
Average travel time

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

31.3 min
Congestion ratio

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

18.2%
Drivers’ average age

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

41.7 yrs
Drivers’ average income

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

$116,623

A typical monitored road in Williamson County, Texas sees 8,688 vehicles per day, while its 1,411 miles of monitored roads together handle 14,018,154 vehicle-miles traveled per day (≈5.1 billion per year). About 1 in 13 vehicles is a truck, fewer than the 1 in 10 across Texas.

Busier roads than 96% of counties in Texas

Williamson's average daily traffic volume is 26% higher than the state average - 8,688 vehicles per day against 6,895 - suggesting more traffic load per road - a busier backdrop for retail sites, at the cost of slower access. Network-wide, Williamson accounts for about 1.9% of Texas's statewide total of vehicle-miles. By volume, Williamson's 8,688 vehicles per day outpaces 96% of counties in Texas.

At 31.3 minutes, the average travel time matches the state level closely. Its average travel time of 31.3 minutes is shorter than 84% of counties in Texas.

Congestion is somewhat higher than the state level, at a ratio of 18.2% (11% higher) - crucial for traffic control improvement and logistics planning.

Highway vs. Non-Highway Traffic Analysis

highway traffic icon

Highway Traffic in Williamson County, Texas

Trafficvehicles per day22,512
Trucks11.2%
Average travel time38.1 min
Congestion ratio35.2%
Drivers’ average age41.3 yrs
Drivers’ average income$108,265

Travel in Williamson County, Texas splits roughly evenly, with about half of it (47% of vehicle-miles) on highways. The average highway carries 22,512 vehicles per day, 187% more than the average non-highway road in the same area, which carries 7,837 vehicles per day.

With 18% of the road miles (253 miles in 1,540 segments), highways punch above their length, carrying 6,603,966 vehicle-miles traveled per day (≈2.4 billion per year).

By highway travel volume, Williamson outranks 96% of counties in Texas.

More highway trucks than 85% of counties in Texas

Highway truck concentration here runs 18% lower than the state average, at 11.2%. Highways here mostly serve passenger trips, so local access matters more than long-haul routing for logistics operators.

Williamson's highway truck share (11.2%) is lower than 81% of counties in Texas. 85% of counties in Texas see fewer highway trucks per day than Williamson's roughly 2,524.

non-highway traffic icon

Non-highway Traffic in Williamson County, Texas

Trafficvehicles per day7,837
Trucks4.6%
Average travel time30.9 min
Congestion ratio17.2%
Drivers’ average age41.9 yrs
Drivers’ average income$120,563

Travel in Williamson County, Texas splits roughly evenly, with about half of it (53% of vehicle-miles) on local roads. On the average non-highway road, that comes to 7,837 vehicles per day.

Local roads make up 82% of the monitored road miles (1,158 miles in 25,027 segments) but carry less than their share of travel: 7,414,189 vehicle-miles traveled per day (≈2.7 billion per year). The truck share on non-highway roads is 4.6%.

Drivers from higher-income areas than 98% of counties in Texas

Non-highway roads carry a truck concentration that's 59% lower than the highway network.

Non-highway congestion (17.2%) runs slightly higher than the state level (7% higher).

Williamson's average driver income is higher than 98% of counties in Texas. Williamson's median driver age is lower than 83% of counties in Texas.

Time-of-Day & Seasonal Patterns

peak hours icon
Peak Traffic Windows
Weekday peaks:
A long morning plateau from 7:00 AM to 12:00 PM and PM peak 4:00 PM–7:00 PM, with volumes reaching approximately 73% higher than the daily average.
Weekend traffic:
Weekend traffic is about as busy as on weekdays (-4%): leisure and through trips largely replace the commute.
seasonal traffic icon
Seasonal Fluctuation
Busy season:
Traffic is nearly flat through the year: even May–July, the busiest stretch, runs only +4% versus the annual average.
Lowest month:
January is the quietest month, with volumes -10% versus the annual average - the usual winter low.

Data Finding: Hourly & Seasonal Patterns

In Williamson County, Texas, the peak hour concentrates about 7% of the day's traffic, and traffic stays steady through the year (+4% in high season).

Williamson County vs. Texas Traffic Comparison

The average daily traffic per road sets Williamson County apart: 26% above the Texas average. Its truck share, by contrast, is 21% below.

MetricWilliamson CountyTexas averageDifference
Traffic8,6886,895+26.0%
Truck % (Total Traffic)7.7%9.8%-21.2%
Truck % (Highway)11.2%13.8%-18.5%
Avg. Travel Time31.3 min32.6 min-4.1%

How Williamson County compares

Williamson County against nearby counties

Williamson 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. Bigger and busier at once: more road than the areas around it and heavier traffic on it, which makes it the centre of gravity for travel in this part of the map.

Williamson County and the 4 nearest county-level areas by centroid distance, with the Texas average for scale.
AreaAverage daily trafficTruck shareDaily vehicle-milesAverage travel timeCongestion ratio
Williamson County8,6887.7%14,018,15431.3 min18.2%
Bell County, Texas7,3079.8%9,002,02133.5 min17.1%
Travis County, Texas9,7187.2%27,140,61732.9 min20.9%
Burnet County, Texas6,8517.6%1,955,60235.1 min15.7%
Milam County, Texas3,61910.9%940,11842.1 min8.6%
Texas average6,8959.8%N/A32.6 min16.4%

Williamson County ranked within Texas

Average driver income places Williamson County #5 of 254 in Texas - the top quarter of the state.

Williamson County ranked among 254 county-level areas in Texas (1 = highest); measures without data in every county rank a smaller field, down to 227.
MeasureWilliamson CountyTexas rank
Traffic volume (AADT)8,688#10 of 254
Highway vehicle-miles per day6,603,966#9 of 227
Truck share on highways11.2%#184 of 227
Highway trucks per day2,524#34 of 227
Average travel time31.3 min#213 of 254
Average driver income$116,623#5 of 254
Average driver age41.7 yrs#210 of 254

The two ends of this table sit far apart: #5 of 254 on average driver income, against #213 of 254 on average travel time.

Busiest roads in Williamson County, Texas

On their busiest stretches, the three busiest roads in Williamson County carry 108,235 vehicles a day on average, 12.5 times the typical road in the county (8,688).

Purple Heart Trail leads with 121,879 vehicles a day, 15,494 of them trucks (12.7%). It tops the truck ranking too, with the most trucks.

Freight stands out on I 35 and Pickle Parkway: trucks are 16.6% and 15.6% of the traffic there, against 7.7% county-wide.

I 35 carries longer journeys than most roads here, with a median trip of 48.8 minutes against 31.3 county-wide.

Ranked by daily traffic (AADT)

Cars and light vehiclesTrucks
1Purple Heart TrailMotorway · 121,879vehicles15,494trucks · 12.7%
Road class
Motorway
Congestion ratio
87.4%
Median trip time
41.1 min
Drivers’ median age
40.9 yrs
Drivers’ average income
$103,246

Delays build on Purple Heart Trail: its congestion ratio of 87% over free-flow time is well above the county's 18%.

2Highway 183Motorway · 113,827vehicles6,816trucks · 6.0%
Road class
Motorway
Congestion ratio
72.4%
Median trip time
33.0 min
Drivers’ median age
40.9 yrs
Drivers’ average income
$120,179

Travel on Highway 183's busiest stretch runs 72% over free-flow time, against 18% across the county, so expect slower peak hours.

3I 35Motorway · 89,000vehicles14,752trucks · 16.6%
Road class
Motorway
Congestion ratio
64.2%
Median trip time
48.8 min
Drivers’ median age
41.5 yrs
Drivers’ average income
$96,485

At 10.2 times the county average, I 35 draws drivers from neighborhoods averaging $96,485 in household income.

4Mopac ExpresswayMotorway · 64,570vehicles4,405trucks · 6.8%
Road class
Motorway
Congestion ratio
36.7%
Median trip time
33.2 min
Drivers’ median age
41.1 yrs
Drivers’ average income
$119,324

A main artery: Mopac Expressway's busiest stretch carries 7.4 times the county average; trucks are 6.8% of it, below the county-wide 7.7%.

5Research BoulevardPrimary road · 63,756vehicles2,223trucks · 3.5%
Road class
Primary road
Congestion ratio
39.4%
Median trip time
32.9 min
Drivers’ median age
41.1 yrs
Drivers’ average income
$119,944

Research Boulevard is a trunk route for the county, carrying 7.3 times the county average on its busiest stretch; trucks are 3.5% of it, below the county-wide 7.7%.

Ranked by trucks per day

Cars and light vehiclesTrucks
1Purple Heart TrailMotorway · #1 by traffic121,879vehicles15,494trucks · 12.7%
2I 35Motorway · #3 by traffic89,000vehicles14,752trucks · 16.6%
3Highway 183Motorway · #2 by traffic113,827vehicles6,816trucks · 6.0%
4Mopac ExpresswayMotorway · #4 by traffic64,570vehicles4,405trucks · 6.8%
5Pickle ParkwayMotorway · 24,607vehicles3,828trucks · 15.6%
Road class
Motorway
Congestion ratio
24.7%
Median trip time
46.6 min
Drivers’ median age
41.9 yrs
Drivers’ average income
$113,126

Drivers on Pickle Parkway are on long journeys, a median 46.6 minutes against 31.3 county-wide: a through route more than a local street.

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

WilliamsonDepartment 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 Williamson County

The same traffic breakdown for the areas closest to Williamson County, Texas.

Need segment-level traffic data?

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