The correct answer actually should -and could- be 0 gallons if they simply cycle to work. Granted, that requires them to have the right infrastructure available, but if (once) that existed, the vast majority of the work force could cycle to work happily. Most people don't live 20 miles or more from where they work
It could also be 0 gallons if the busses are electrified, or if the rail system is expanded, or if we stop pushing office workers to commute every day.
I'm just sayjt that we need to change the way we live. Like you said, people should not be required to work in offices anymore. If they physically need to be at locations, let them walk for short distances, cycle for medium distances and use public transportation for large distances.
Most cities in the world have been redesigned over the past 80 years for cars. It's insane and it left most cities awful places to live in. Almost all Dutch cities have been redesigned for people. So people walk and cycle because they can, and the cities look and feel amazing and beautiful.
45 minutes is a long time near nightfall, though... Honestly I'd rather take a bus at 5PM, even at 12km, since there are other people and it feels much safer.
I was being facetious; ambulance fuel use is a silly comparison :)
Listening to all y'all winter cyclists I lament that I live in a city where the bike lanes are where the city piles up the snow it plows off the car lanes on the streets. RIP me. It gives me hope and happiness to know that there are cities that don't do this!