Yes. Signficantly.
Hybrid vehicles in general are much quieter than regular cars. So in that theory, yes, hybrid trucks would be quieter, and take less gas to run as well.
quieter, quietestquieter, quietest
Light
quieter
No, louder sounds do not travel faster than quieter sounds. Sound travels at the same speed regardless of its volume.
quieterOur house is quieter than yours
Low sone is quieter than high sone. Sone is a unit that measures the perceived loudness of a sound, so a lower sone rating corresponds to a quieter sound.
He is snoring louder than a bear. Resting quieter than a baby after she is fed.
Comparative
The degree of comparison used in the sentence "Carol needs a quieter office than she now has" is the comparative degree. This is indicated by the use of the word "quieter," which compares the noise level of the office Carol currently has to the office she desires.
compressor runs quieter than usuAL and overheats
Just, simply, Lighter than Air Vehicles are lighter than air, so that makes them fly, and Heavier than air vehicles are heavier than air, but they use airfoils on the wings to fly.