If they own a one-truck company and drive for themselves, profit will be dependant on their margins.
For example, a driver that drives from CA-FL and back year-round will make $60,000 to $90,000 profit, depending on how many miles they drive and how they run their company.
If they buy it.
An average semi 'tractor' is about 30 feet long.
An average semi-truck driver can make up to 50,000 a year as an independent truck driver. They can make more depending on the load and the company that offer a price for the traveling.
I guess you could get by with it if you wanted
This will depend on year and brand of truck, a driver record, number of miles truck will be driven in a year, and type of freight a driver will be hauling
better y=to use it
The average fuel economy of a semi truck is between 5 and 7 mpg when loaded.
Average is 70 feet
70 feet
800 a day
"Semi truck" has become common usage for a Class 7 or 8 truck driver pulling a trailer which is mounted by a fifth wheel, but can be applied to any truck pulling a trailer which is fifth wheel mounted.
80,000 to 100,000 US dollars