OT
Tl;dr; semi is a reasonable thing to build.
Clearly increasing the # of AVs is best for the mission (much larger number of EV miles means more missions stopped) and for the bottomline.
I'd be happy to say Semis should be the priority if someone shows making Semi removes more emissions in 5 years than making robotaxis. Take into account how much cash robotaxis can generate and how many more batteries can be produced because of that etc.
Miles replaced is not the key factor, emissions removed is (fuel consumption and type).
Taxis are trending toward higher efficiency gasoline vehicles already (Prius for instance). Replacing a 40MPG or higher gasoline or gas hybrid removes much fewer CO2, NOx, and particulates than removing a diesel semi.
Semi: one million miles in 2.6 years (80% utilization 50 MPH average speed)
Taxi: one million miles in 5.5 years (70% utilization 30 MPH average speed)
Semi: 2x the mileage
Semi: 6 MPG
Taxi: 36 MPG
Semi: 6x the fuel usage
Combined: semi 12x the fuel burned per year
Fuel type:
Semi: diesel 2.68kg of CO2/L
Taxi: gasoline 2.31kg og CO2/L
Semi: 15% more CO2 per unit fuel.
Semi 13.8x the CO2 per year.
Particulates: semi is higher
Replacement type: semi replacement age is higher than taxi, thus an e-semi replaces old more polluting tech.
Lifespan: robo-taxi is 1 million mile powertrain like semi, but I expect semi will be be refurbed more times (new seat, overhaul drive units, swap packs, downgrade LR to SR) at 7.5 year per semi, the is 3x the total miles.
Market: in the US there are approximately 2 million semis
In 2016 the US had 305,000 taxi drivers. Assuming 2 shifts, under 200k taxis.
Semi: 10x the market
Cell usage:
Semi 600 kWh SR, up to 1,000kWh LR
Taxi: 60 kWh
Semi: 10 to 16x the cells.
At a 10x ratio of emissions per year, and 45x over lifespan, SR semi is better at reducing GHG+ particulate than replacing taxis. Over full life span, LR semi is better than taxi.
Market is 10x for semi, allowing up to 450x per year reduction in the US. Tesla growth is limited by things other than $$, and Tesla can use a lot of semis internally (materials, car haulers) which produce revenue also. With a proven revenue record, Tesla can fund expansion with bonds or other means vs cash.
Also faster and logistically easier to build 1/10 the number of semi.
Plus the general improvements of semi average speed, reduction of pollution in urban areas, efficiency improvement over topography which add to the benefits.