Answer: 46 inches Explanation: usually 4 is ok 
RAMOS CONCRETE CONSTRUCTION 
Answer: 24 inches Explanation: That depends largely on the subgrade materials, and traffic serviced by the driveway, but on stiff clay soils, 24" of aggregate base is typically adequate to bridge irregularities and produce a smooth, friction minimized subgrade. 
Maven Group LLC 
Answer: 02 inches Explanation: Thickness required depending on condition of surface being poured on. 
BAT Concrete llc 

ProMatcher 
Answer: 24 inches Explanation: It depends on the soil properties below. 
QUALITY CONTRACTORS 
Answer: 46 inches Explanation: The gravel base for a driveway should be a minimum of 4 inches deep. 
Colorado Concrete 
Answer: 02 inches Explanation: 2 inches is recommended 
alvaradomasonry 

ProMatcher 
Answer: 46 inches Explanation: A base is usually used for drainage, uniformity, or leveling off the area in most residential cases. 
Black Dirt Services LLC 
Answer: 46 inches Explanation: base should match concrete thickness 
LPG,LLC 
Answer: 46 inches Explanation: This is as per code requires 
h and h company 