I think there's disagreement about what 1% means - far less than 1% of my time spent operating a car involves interaction with a UPS truck, but more than 1% of

I think there's disagreement about what 1% means - far less than 1% of my time spent operating a car involves interaction with a UPS truck, but more than 1% of my trips do. Asking as someone with no first hand experience with these systems - do they complete 99% of trips with no disengagements or unexpected behavior, 99% of time driving, something else?