Noise during a night delivery does not come from one source. Engine or refrigeration-unit noise needs a different response from handling sounds made by doors and castors. First record when each sound occurs.
A short record for each delivery
Note the time and location, whether the engine is idling, whether the unit is running, door openings and vehicle used. If possible, measure sound from the same device and position; also note nearby noise or weather conditions.
Change one practice, such as castor material, unloading sequence or door handling. Measure again at the same location with a comparable load and task. This helps keep the effect of the change separate from other conditions.
A passive insulated container may reduce the need for a running refrigeration unit during delivery; product conditions, route duration and ambient temperature still need validation. Castor and handling noise may remain.
Check store, building and local requirements before changing delivery hours. Matching noise complaints to time and location shows which stops need a change in procedure.
