A toll booth owner wants to accept zero confirmation transactions (because waiting for confirmation would lead to long lines at the toll booth) and open the gate as soon as the transaction (with integrated payment ID) reaches the mempool.
Is there a way the toll booth operator can calculate the cost of a double spending attack against be Monero network based on current network hashrate?
The toll booth operator knows there are some tech savvy drivers who regularly use his road (that are smart enough to know how to attempt a double spend). However he wants to measure that impact against the lost revenue that will result if long lines cause some drivers to start taking alternative routes.
Accepting cash or credit cards is not an option because some of the users of his toll booth frequently never carry cash and value their privacy too much to use credit cards.