Much as they have features for walk / bike / transit traffic, they could suggest step-by-step carpool instructions: "1. meet with (other Google Map carpool us

Much as they have features for walk / bike / transit traffic, they could suggest step-by-step carpool instructions: "1. meet with (other Google Map carpool user) X at location Y. 2. In one car, both of you drive to location Z." Obviously, huge challenges here (is person X a serial killer, etc.) But Google can handle moonshots.