In a one-vehicle household the average daily mileage is about 30 miles, according to the 2017 National Household Travel Survey. In a two-vehicle household, the first vehicle averages nearly 40 miles in a day; in a three-vehicle household, the first vehicle averages over 40 miles per day. This trend continues and the average daily miles of the first vehicle in a six-vehicle household is about 50 miles a day. Daily miles for the second vehicle in each of these categories is 50-55% that of the first vehicle.
Note: The vehicles were sorted based on vehicle miles and assigned vehicle numbers accordingly (i.e., the household vehicle with the highest VMT was assigned vehicle 1, the vehicle with the second highest VMT was assigned vehicle number 2, and so on).
Source: U.S. Department of Transportation, Federal Highway Administration, National Household Travel Survey website, accessed June 6, 2018.