Would car parts easy to loose or come off while driving?

I always hear some sounds while driving on the highway. Some of them must be little stones hit my car, but sometimes I hear some sounds seems come from metals.





Would car parts easy to loose or come off while driving?





Or the metal sounds are only stones hit my car's metal?


(the bottom of the car are made of metals, such as CV axises, catalytic converter)|||some parts can fall off if work as been done and not tightened up properly the main thing that falls off r exhaust parts that have rusted through i have seen a wheel come off a car but these r all big parts that u would c and avoid so it is stones that u would hear hitting the under side of ur motor|||it depends on what parts your talking about. there are some parts on a car that will work a little loose over a period of time. take oil pan or valve pan bolts for instance, they tend to loosen up over a period of time.|||ive never had any fall off. it could be your tranny grinding.