Traffic Counts | Traffic Engineering | Public Works & Utilities

Public Works & Utilities >> Traffic Division >> Traffic Counts

Look up Traffic Count Data

Traffic Counts for All County Roads (PDF, 58.62 KB)

Why Pierce County Counts Traffic

Pierce County uses electronic traffic data recorders to collect daily traffic counts on most arterial roads. Traffic counts are conducted on a regular periodic basis, and are primarily used to monitor roadway use and changes in traffic flow. Counts are also used for planning improvements throughout the road system.

Annual Average Daily Traffic (AADT)

The Annual Average Daily Traffic (AADT) is the total volume of traffic on a segment of road for one year divided by the number of days in the year. We generally set up traffic counters for 24 to 48 hours and then use day and month adjustment factors to give an estimate of the AADT.

Most arterials are counted every 1 to 2 years. There are more than 10 locations in the county where we collect traffic count data 24 hours per day, all year long.

Frequently Asked Questions

Q: I see a counter on my road. Does that mean it's going to be widened?

A: In most cases, no. We routinely count traffic so that we can be aware of any changes in traffic flow, such as gradual increases due to growth or other changes due to traffic circulation in the area. Traffic counts are, however, routinely used in the planning and design of road improvements.

If you are interested whether an improvement project is proposed for a particular road, you can look at the County Transportation Improvement Program.

Q: Why are some counts listed every year and some aren't?

A: Locations are typically counted every year or every other year based on growth management and traffic monitoring needs.

Q: Why isn't my road listed?

A: Only County arterial roads are routinely counted. We do collect data on non-arterial County roads when there is a specific need to know the traffic volume. We do not collect traffic count data on private roads, state highways, or roads inside the corporate limits of cities.

Q: When will you count my road?

A: If you live on a County arterial, a location along your road will likely be counted within the next 24 months. Local (non-arterial) roads are only counted as needed on a case-by-case basis.

Still have questions?

Please email your traffic count questions, or call us at (253) 798-7253.

A traffic engineering technician sets traffic counting tubes across a roadway.