If I place magnetic signs on my vehicle, can I then write off all the expenses of the vehicle, not just my business-use part? (T.S., Antioch, CA)

No. The IRS says this about an advertising display on your vehicle: “Putting display material that advertises your business on your car does not change the use of your car from personal use to business use.”1

In other words, you treat your car as if the signs do not exist. ... Log in to view full article.