Where the empty miles come from
A robotaxi drives empty between dropping one rider and reaching the next. California carriers file, per census tract, how many trips started and ended there — so the imbalance between the two maps where that empty repositioning is generated. It is the geography behind the deadhead ratio, a level of detail no operator publishes.
SF Bay Area — trip origins against destinations
Each tract is shaded by the net between trips that ended there and trips that started there. Hover a tract for both counts. Scroll to zoom, drag to pan.
Why an origin-destination map is a deadhead map
What the imbalance actually tells you.
Every trip has to be balanced by the fleet: a vehicle that ends a trip in one tract has to get to wherever the next trip begins. When a tract takes in far more trips than it sends out — a downtown at close of business, an airport, a stadium — the vehicles that arrive there have to leave empty to find their next rider. That empty leg is deadhead, and this map shows the tracts that generate it.
The figure it grounds is the deadhead ratio: the share of all driving that carries no passenger. That page says how much of the driving is empty; this one says where the emptiness is produced. Only the metros with a tract-level trip filing appear here — Waymo files origin and destination counts for its densest service areas and redacts them elsewhere, so the map is a window, not the whole picture.