A report released in July by the Sam Schwartz Transportation Research Program at Hunter College – in collaboration with Open Plans – showed that autonomous taxis would dramatically increase traffic congestion on New York City streets. The study found that Waymo cabs spend far more time driving around without passengers than comparable human-driven Uber and Lyft vehicles.
According to the study, California Waymo taxis travel 0.71 miles empty for every one mile. But in New York City, app-hail vehicles drive empty for 0.49 miles for every one mile with a passenger. That 14.8% gap would translate to tens of thousands of additional vehicle miles every day.
The number of additional miles depends on how many robotaxis replace existing taxi trips, according to an article in StreetsBlog NYC. If deployed robotaxis just add to existing taxi trips, the additional number of vehicle miles traveled (VMTs) will be much higher than if robotaxis slowly replaced existing taxis. VMTs increase in both scenarios. If 2,000 new autonomous taxis show up in New York City and there is no commensurate decrease in standard taxi trips, there will be 293,800 more VMTs in NYC every day, equaling more than 3,750 trips in Manhattan every day. If robotaxis slowly replace human drivers, there will still be an increase in VMTs because of the 14.8% higher “deadheading” rate for robotaxis.
In California, robotaxis spend roughly 58% of their empty time in a parking space, but analysts say it’s far less likely in NYC that a robotaxi would be able to find an empty space between rides. The report says that for every 1% decrease in parked time, a robotaxi experiences a 1.5% increase in deadheading. If robotaxis in New York were parked just 25% (vs. the 58% of the time in California), it would translate to roughly another 62,000 vehicle miles traveled every day in New York.
Source: StreetsBlog NYC
