gradient , or rate of change is always varying. An average speed for a journey can be found from a distance-time graph by working out the gradient of the line between the two points of interest.

The study below the main chart utilizes a 10-day rate of change function as well as Bollinger bands that are tuned to 20 days and 1.6 standard deviations.

An average speed for a journey can be found from a distance-time graph by working out the gradient of the line between the two points of interest. This is like using a car’s milometer and clock ...