Is the productivity measure of shipments per day per truck still useful? Are there alternatives that might be effective?

What, if anything, can be done to reduce the daily variability in pickup call$-$ins? Can the driver be expected to be at several locations at once at $5$:$00$ P$.$M$.?$

How should package pickup performance be measured? Are standards useful in an environment that is affected by the weather, traffic, and other random variables? Are other companies having similar problems?