i am confused with this as well.  i did the clients tax return last year.   $50000 car took bonus depreciation of 18100.  from what i'm reading in the irs instructions, it says the second year you can take the $18000.  i have a left over basis of $31,900.  why can't i take the 2nd year bonus deduction as outlined below:

The maximum deduction amounts for most passenger automobiles are shown in the following table.
Maximum Depreciation Deduction for Passenger Automobiles (Including Trucks and Vans) Acquired After September 27, 2017, and Placed in Service Before
2024
Date Placed in service                                   
            1st.            2nd      3rd.       4th & Later
2023 $20,200 1 $19,500 $11,700 $6,960
2022 $19,2002 $18,000 $10,800 $6,460
2021 $18,2003 $16,400 $9,800 $5,860
2020 $18,1004 $16,100 $9,700 $5,760
2019 $18,1004 $16,100 $9,700 $5,760
2018 $18,0005 $16,000 $9,600 $5,76

Thanks for your input.