Delivery trucks run during the day mostly. Cities may prohibit deliveries at night for noise reasons. Deliveries at night might be more likely to be stolen, etc. Could be able to fix the first issue with the quietness of EVs perhaps.
* The extremely loud engine and exhaust. (They are loud and unpleasant to listen to - it ain't no Ferrari)
* The slamming of the doors open and closed.
If I hear a loud agricultural sounding engine and then a loud slamming sliding type door... I know it's UPS - 100%. I don't even need to look outside.