Self-Driving Taxis Travel Empty 44% of the Time: And Traffic Increases

The promise of future mobility was monumental: to free cities from congestion through fleets of smart vehicles capable of optimizing every single journey. It took just over a decade to go from the DARPA Grand Challenges to the commercial debut of Waymo's services in California, initially supervised by a safety driver and now fully autonomous. But the reality, based on real data accumulated over more than a thousand days of service, tells a different story.

Robotaxis are not reducing road traffic, behaving in a manner quite similar to traditional ride-hailing services like Uber and Lyft.

The numbers come directly from the official reports that Waymo has presented to the California Public Utilities Commission. A thorough analysis conducted by Awad Abdelhalim from the MIT Transit Lab and published in Transport Findings examined the period from August 2023 to December 2025. During this timeframe, Waymo's fleet completed 13.8 million rides, transporting 19.3 million passengers over a total distance of 86.3 million miles (about 138.8 million kilometers) and recording a monthly growth rate of 15%. The problem analyzed by Abdelhalim is not about public demand but rather the logistical efficiency of the actual trips extracted from the report.

The Phenomenon of Deadheading and Unresolved Issues in the Fleet

The core of the study focuses on the so-called deadheading, or the percentage of road traveled by completely empty vehicles. At the beginning of the analysis period, only 36% of the miles covered by Waymo had an actual passenger on board. With the expansion of service and the optimization of ride assignment algorithms, this percentage rose to about 56%, stabilizing at that threshold. This means that about 44% of the total miles are driven by electric vehicles traveling with no one in the cabin.

These ghost vehicles fall into two operational categories: those that move to reach the customer pick-up point and those that simply cruise around waiting for the algorithm to assign them a new route. Although Waymo has managed to reduce the share of empty miles through the introduction of service on urban highways and the overall increase in fleet density, the barrier of 44% of empty mileage remains a significant limit that risks thwarting the environmental benefits of the transition.

The autonomous driving sector, backed by over $100 billion in global investments, continues to defend the technology by highlighting roadway safety data. Waymo has shown that its Jaguar I-Pace vehicles cause fewer accidents than human drivers, with significantly lower insurance claims, although specific issues related to managing school buses or flooded roads remain unresolved. However, if the ultimate goal was to decongest urban centers by eliminating private cars, for now, the result is merely a new fleet of vehicles that often travels empty through city streets.