Why does it matter if I have another vehicle for personal use under self-employed business vehicle questions?

[tessfam4]

If I use a personally-owned vehicle for my self-employed business (and keep track of business mileage) as well as for personal use, what does it matter if I have another vehicle available for personal use? What is the purpose of this question?

[IsabellaG]

The IRS wants this information to establish if the business mileage that you are claiming is reasonable. If another vehicle is available for personal use, then a higher percentage of business use using your business vehicle would make sense.