Traffic Engineering
What Is a Roundabout Count?
Entries, exits and circulating movements at roundabouts.
By SWAT Alliance Editorial Team · Updated 25 August 2026
Insight at a glance
A short visual checklist for better study decisions.
Use the article as a starting point, then confirm the project-specific scope, method, review and output with the delivery team.
Question
What decision should this evidence help someone make?
Scope
Which locations, movements, classes and periods matter?
Review
How will completeness and definitions be checked?
Output
What format will make the result easiest to use?
Short answer
A roundabout count records where traffic enters a roundabout and where it exits, using named arms and an agreed entry-to-exit matrix.
Why the movement matrix matters
A roundabout is not simply a total at each arm. A matrix connects each included entry to its exit path, making distribution through the layout visible.
Set the site rules first
Define arm names, lanes where relevant, active-travel crossings, classes and periods before the count. These details become the reference for every output table.
Visibility and quality
Large, multi-lane or obscured sites may need multiple viewpoints. Check that each included entry and exit can be followed before analysis begins.
Frequently asked questions
Do roundabout counts include circulating vehicles?
Only if the agreed matrix or scope asks for them; entry-to-exit movements are the normal basis.
Can it include cycling?
Yes, with a separate route/crossing rule where needed.
Go deeper
Roundabout Count Methodology
A structured way to record entries, exits and circulating movements at a roundabout.
View Methodology →Related services