How would i make a car delete itself if a player doesn't get into it within 20 seconds?

seat = script.Parent
s = script


function onChildAdded(child)
	if child.Name == "SeatWeld" then
		local human = child.part1.Parent:findFirstChild("Humanoid") 
		if (human ~= nil) then
			print("ln")
			
		end
	end
end

function onChildRemoved(child)
	if (child.Name == "SeatWeld") then	
		local human = child.part1.Parent:findFirstChild("Humanoid") 
		if (human ~= nil) then
			print("Out")
			wait(20)
			script.Parent.Parent:Destroy()
		end
	end
end


script.Parent.ChildAdded:connect(onChildAdded)
script.Parent.ChildRemoved:connect(onChildRemoved)

Ok, thanks for reading and hopefully answering! So anyways, when a player gets into a car and gets out, the car will delete it self with his code:

if (human ~= nil) then
			print("Human OUT")
			script.Parent.Parent:Destroy() -- this one
		end

but im trying to use a ultimate driving type car spawner, but of course people sometimes dont go into the cars So how would i make a car delete itself within 20 seconds if nobody goes into it? Thanks!

You may try this:

local seat = script.Parent

wait(20)

if not script.Parent.ChildAdded then
	script.Parent.Parent:Destroy()
end

if script.Parent.ChildAdded then
	return
end