But sadly, no central planner can know which people need to go where when and how much value should be attached to each trip. Only the individuals themselves know this.

Correlation predicates typically compare some key value in the event, such as a unique trip identifier, with a metric containing the same key.

According to a popular saying the value of life is not measured in the number of years, the same way the value of a trip is not calculated by the number of destinations!