Traffic Data
Queue Length Survey Explained
What a queue study observes and reports.
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 queue length survey records the extent of a vehicle queue on a defined approach, using an agreed reference point and measurement unit.
Define what a queue means
Specify whether the unit is vehicles, metres or both, where the queue begins and whether the result is a maximum, average or regular sample.
Capture the full approach
A video view must include the reference point and the expected queue extent. A queue extending outside the frame is a limitation, not a zero.
Use the result carefully
Queue extent describes observed conditions. It does not by itself establish delay, capacity, cause or a future design outcome.
Frequently asked questions
Can a queue be counted by lane?
Yes, if lane boundaries and the observation rule are stated in the brief.
Should signal cycles be included?
Only when the scope specifies how they are recorded or analysed.
Go deeper
Queue Length Survey Methodology
A field or video method for recording queues on defined approaches.
View Methodology →Related services