I am ONLY USING THIS as AN EXAMPLE......I know about about all the other auto deductible related expenses you can take.  I'm not requesting to provide the entire picture, but thank you for mentioning this.

For 2019:
1st year in service.
T/P annual mileage:  200
Business Miles:  100
Actual Expenses - FOR THIS EXAMPLE ONLY - $85
Business %:  50
STD Mileage rate: .58/Busn. Mile

Actual Vs. Std?
  1.  Actual Deductible - (50% of $70) = $35
  2.  STD - (100 X .58 = $58 & 50% of $15) - $66

In this LIMITED EXAMPLE ONLY, T/P would elect STD.

Does this provide a complete picture for you?