It seems this was never fully addressed and the original topic fits my situation to a t. 3 vehicles on the platform for business use- self employed 20k income. 
so here’s what I can clarify: 

Typically there is a commission or acquisition fee paid to Turo for the acquisition of the client. The self employed individual with the 1099 or self employment income does not see this money, and in my case it is approx. 40%. Then you have the expense of the vehicles you rent out to other individuals. We maintain, wash, sanitize and otherwise completely care for the vehicles. Everything EXCEPT fuel replacement, which is handled by the end renter under the rental agreement. Typically the end renter replaces the fuel however there are times where they bring back cars with less fuel and we incur fuel replacement costs. Otherwise the owner (self employed individual) incurs all of the vehicles cost. Insurance, registration, loan interest *if any*, repairs, maintenance -oil-tires-washes-brakes- you name it). Most of us that do this and take it seriously have dedicated cars for this purpose. In my case I own 5 vehicles, 2 “personal” cars and 3 dedicates 100% for Turo rentals. In my case 1 of my 3 had maintenance costs exceeding standard mileage deduction- so I claimed actual expenses. The other two it was slightly more of a deduction to claim standard mileage vs. actual expenses expenses. That brings us to the question... if you yourself are not “operating” these vehicles can you claim standard mileage? I have yet to get a clear answer from anyone. Some CPA’s say yes and some say no. Since we are not fueling the cars, and that’s a consideration for the standard mileage deduction (this year 57.5 cents per business mile). Here’s my thoughts previously posted in reply to this question on another post thread: 

Any car share (Turo or any rental service) self-employed person should be able to do standard mileage  deduction and back off fuel costs easily WITHOUT receipts. For example if you have a vehicle that has 10k business miles and you’re claiming standard mileage deduction of 57.5 cents thats a deduction of 5750. Couldn’t you simply take the fuel range of the car (ex 400 miles) divide the total mileage by the cars range and divide that to determine how many tanks of fuel, in this case 25 and then multiple that by the fuel capacity of the tank (ex 23 gallons), finally multiply by the average cost of fuel (ex 2.50) which gives us $1437 and then deduct that from the total “standard mileage deduction” so $5750-$1437= a total deduction of $4313. I’m not an accountant or a cpa but is there any reason this is NOT an acceptable way to go about this?