The Separation Histogram report provides a graphical distribution of the separation (in time) between vehicles.
Separation Histogram Sample
The X-axis scale can be changed, by right-clicking the report and selecting Properties. This allows for examination of the behaviour of close-following vehicles.
The Speed vs Separation dispersion plot also examines this behaviour, but takes into account vehicle speed.
The definition of separation as either headway or gap can be set in the report's Advanced Profile options.