a 100% deduction might be available but you are going to have to tell the IRS that you only use this only for the rental properties - no personal use. you are going to need written records to substantiate this use. (the first question is really supplying the mileage - total, business and non business which would have to be zero. then you are going to have to answer a question about maintaining records.
finally you are going to have to allocate the deduction among the properties.
a 100% writeoff for 100% business use of a qualifying vehicle goes back years. there is no new law.