Meaning of green/yellow/red and gray bars in graphs

Preamble

While browsing DEM graphs you may sometimes see colored bars or shaded areas — red or gray — indicating incomplete data. What do they mean?

Above most graphs you’ll find a top summary bar colored green, yellow, or red. Each color has the following meaning:

In the example above, the Speed Index could be improved.

Hovering over segments in this top bar highlights matching segments in the chart.

Red vertical bars that appear on your scenarios highlight errors that occurred during execution.

To view the error details, hover over the red bar — DEM will show at which step the scenario stopped and why.

Clicking the bar also often offers a screenshot of the page at the time of the error, which is useful to understand what happened.

You may also see gray bars on some DEM charts. These simply indicate that data could not be received at the measurement time.

This typically happens for two main reasons:

you are viewing a period when the probe was not scheduled to run (e.g. scenario not yet created or temporarily disabled)
the site did not respond at all (for example during a server restart or if the server was so overloaded it could not send data)

In general, gray bars appear when the infrastructure was unable to produce measurement data.