#GreatThingsThatHappenedOnTransit - The Bus v Tesla

Elon Musk has been getting a lot of flak recently for his comments about public transit, and rightfully so. On the surface, he seems to want to save the world and reduce our reliance on oil. Below the surface, is he simply a guy trying to sell cars? Regardless of his motives, A Tesla will never be as space efficient as a bus, and in a city environment, efficiency of road space is a top priority. Here's a quick comparison of a bus and a Tesla.

I started with a local bus, a TransLink owned New Flyer E40LFR, Thius bus is 12.6m by 2.6m, taking up 32.76m2 of road space. It has a capacity of 77 passengers, thus takes up 0.425m2 of road space per passenger at a standstill.

Tesla's latest Model 3 is 4.694m by 2.088m, taking up 9.801m2 of road space. It has a capacity of five people, thus takes up 1.96m2 of road space per person at a standstill. On a per person basis, the Tesla takes up 4.535 times more road space per person.

These distances are relatively small, but in the grand scheme of things when 1,000 or 10,000 people are trying to get along the same city street, things are a little different. Lets just assume for a minute that that demand of 10,000 people per hour. 10,000 people all on transit would require 130 buses, assuming all were at capacity. Just two buses per minute could accommodate 10,000 people an hour.

Now remove buses from the equation and and those 10,000 people require 2,000 Tesla's assuming each and every one of those Tesla's are full, that's about what an average 4 lane street could accommodate, maybe a little more. Unfortunately, Tesla drivers are not know for their habit of stopping to pick up strangers like a bus does. The reality is that the average occupancy would be more like 1.2, same as any other car, and you would more likely see 8,333 Tesla's. That would be great for sales numbers and share holders, less so for congestion reduction or a livable city.

What would you prefer, 2 buses per minute along the street, or 8,333 Tesla's?

Of course there's a balance somewhere in the middle, both have their place, but a city cannot move the amount of people that needs to move in any kind of automobile, individualized transport solution. For this reason, AV's will be a failure for cities unless they figure out the shared ride.

When you consider moving vehicles, the story does not get any better for Tesla. Safe headway is typically around 2 seconds between vehicles. The Tesla may have slightly better or autonomous braking, reducing it slightly from that of a bus. But when moving the ratio of road space to vehicle occupancy swings further in favour of the bus. With both vehicles travelling at 50 km/h (or 14 m/s) a vehicle moves 28m in 2 seconds.

With the bus taking up 2.6m by 40.6m of road space, it requires an area of 105.56m2. To be fair I dropped the occupancy of the bus to a similar percentage as the average 1.2 occupant car. Approximately 24% of 77 passenger capacity is 19 passengers. Each passenger now takes up 5.583m2 of road space.

The Tesla however, takes up a smaller area of road space, 2.088m by 32.694m is 68.265m2. However, the 1.2 person occupancy means the Tesla requires 56.888m2 per person. Over 10 times the space of the person on the bus.

Given there is more likelihood of the bus being fully occupied on a busy city street than the Tesla. The ratio is only likely to move in favour of the bus. 

Is the Tesla a better option if you live in the suburbs and commute to the city? Perhaps. Is it a good thing for everyone who needs to work in the city to get there in a Tesla? Definitely not! You'd have to be an idiot to think that!