Sec 44AE for heavy vehicles.

a) if assessee owns 2 heavy vehicles having (gross weight 28000kg) but the vehicle was not in use during the year still it deemed income has to be offer for the purpose of income?
b)
and what if he owns 2 heavy vehicle but doesn't want to opt sec 44AE and maintain book of account. Can he just file ROI through ITR 3 or has to conduct audit?