The Driverless Alternative to an Airport Trolley Extender – Voice of San Diego
As a transit enthusiast who often flies from Oklahoma City to visit family in San Diego, I believe that a trolley extension is not suitable to serve San Diego International Airport, whose number of passengers will increase by 25 millions in 2019 to 40 million by 2043.
San Diego needs more frequent, high-capacity airport rail. Having traveled the tram as well as subways around the world from Los Angeles to Singapore, read the work of mathematician and transit analyst Alon Levy on subway construction costs, and commented at meetings of the Association of Governments of San Diego (SANDAG), I became convinced that automated movers, driverless trains that service airports and neighborhoods, are the solution.
On December 16, the Metropolitan Transit System (MTS) presented a feasibility study to study promoting an airport trolley extension that SANDAG listed as Concept 4 in its Airport Connectivity 2019 To analyse.
In the analysis, SANDAG offers three automated shuttle concepts, although one has since been eliminated. The remaining two concepts offer trains running every 2 minutes, while a fourth concept offers trolleys arriving at the airport every 15 minutes. This is especially inconvenient considering that the actual time spent on the trolley to get from the airport to Santa Fe Depot would only be 13 minutes.
Granted, streetcar riders would enjoy a one-seater ride from the airport to downtown, while automated shuttle riders would need to transfer to the streetcar from a station between Old Town and Santa Fe. But being given The SANDAG project to increase Blue and Green line frequencies to 7.5 minutes each, maximum wait times for a trolley to Santa Fe or Old Town would be only 3.25 minutes and 7.5 to UC San Diego, Mission Valley or South Bay. Even though the trolley and automated shuttle concepts have comparable combined wait and travel times, travelers would still prefer the higher frequencies of automated shuttles, as a minute of waiting for a vehicle may seem longer than a minute of travel in the vehicle.
Additionally, automated people movers serve more than 40 airports worldwide and are therefore optimized to accommodate passengers with luggage through level boarding, level floors, wider doorways and wider aisles.
In terms of capacity, an automated mover would also be superior to a cart extender. Most automated airport shuttles can run two-car trains, with capacities of 100 per car or 200 by train. With trains running every two minutes, or 30 trains per hour, the automated shuttle system would move up to 6,000 passengers per hour.
In contrast, each trolley consists of three light rail vehicles, with a maximum of 184 passengers per vehicle, i.e. 552 passengers per train. With trains running every 15 minutes, or four trains per hour, the trolley would move a maximum of 2,208 passengers per hour. That’s less than half the capacity of automated shuttles.
Despite the superior convenience and capacity of the automated people mover, MTS favors an airport cart, indicating that the cart would not depend on the implementation of Central Mobility Hub planning, which would take six to 10 years.
But the automated mover could be built before plans for the central mobility center are finalized. At the SANDAG board meeting on December 3, the Port of San Diego offered land to SANDAG at port headquarters for a transit center. The site, being next to the Middletown train station, would provide excellent automated mover-to-trolley transfer, which, as Colin Parent, director of Circulate San Diego Remarks, would eliminate the need for downtown travelers to travel north past the airport for two miles before doubling back to access the airport. This transfer does not need to be the $2.42 billion Central Mobility Hub that SANDAG is considering. Instead, the transfer should be simple and efficient; a pedestrian bridge or tunnel with escalators, elevators and moving walkways would suffice. SANDAG may later build the Central Mobility Hub at NAVWAR or downtown, and depending on demand, expand the automated people mover system to the Central Mobility Hub.
MTS also considered expanding the airport trolley to destinations such as Liberty Station and Sports Arena. Yet an automated mover is even more expandable than the cart. Singapore and Macau’s light rail systems use automated shuttles to connect residential and commercial districts, not just airport terminals. These trains, being shorter than trolleybuses, require shorter platforms. This is essential to reduce construction costs since, as Alon Levy’s remarks, stations are often the most expensive part of underground subway projects, including the 2nd Avenue subway in New York City.
Not only are SANDAG’s estimated capital costs for the automated people mover lower than the cart on a per mile basis, but automated people movers are driverless, making them cheaper to operate than carts and safe from the driver shortages that forced transit agencies to cut service during COVID-19.
The choice is clear. With superior convenience and capacity, it’s no wonder that even at conservative estimates an automated people mover attracts 17,000 daily users compared to 12,700 for an airport trolley. For the airport to minimize congestion and greenhouse gas emissions, it must maximize transit ridership. It’s time for SANDAG to build an automated mover.