
Electric trucks and vans cut pollution faster than cars - a_w
http://www.bbc.com/news/business-40715793
======
warrenm
Duh?

Seth Godin talked about this (OK, not the "electric" part, but the consuming
fuel part) 8 years ago: [http://sethgodin.typepad.com/seths_blog/2009/08/not-
so-good-...](http://sethgodin.typepad.com/seths_blog/2009/08/not-so-good-at-
math.html). Elaborated upon at
[https://gillesarbour.wordpress.com/2009/08/22/a-little-
math-...](https://gillesarbour.wordpress.com/2009/08/22/a-little-math-from-
seth-godin-for-a-change) and [https://antipaucity.com/2009/08/23/want-to-
reduce-gas-consum...](https://antipaucity.com/2009/08/23/want-to-reduce-gas-
consumption/#.WXtojNMrLgo) at least.

You _always_ get the best "bang for your buck" as a _percentage_ improvement,
not a _numerical_ improvement. Sometimes the numerical improvement is _also_
the better percentage improvement. But not always (nor, even, often).

It's the same math that makes going 10 MPH faster less and less important to
shaving time off your trip the faster your starting speed was.

For example, say you need to drive 420 miles. At 10 MPH (a casual bike rider's
speed), it will take you 42 hours to go 420 miles. Add 10 MPH, _doubling_ your
speed to 20 MPH (about the average driving speed in NYC), and it now only
takes you 21 hours to travel 420 miles.

Add another 10 MPH, increasing your speed by 50% to 30 MPH, and it take 14
hours to travel. Same _numerical_ improvement in speed, but the _percentage_
is lower, so the impact is less. Let's bump by another 10 MPH, 1/3, to 40 MPH.
Your time drops to 10.5 hours. An improvement, no doubt, but not nearly so
impactful. (The quick way to calculate this is for every 1/X speed
improvement, you get a 1/(X+1) reduction in time (for the same distance).
Adding 1/5 to your speed going from 50 to 60 drops your time by 1/6 (from an
hour - for 50 miles - to 50 minutes, for example).)

An average tractor-trailer gets 5-7 MPG
([http://www.answers.com/Q/What_is_the_average_mpg_of_a_tracto...](http://www.answers.com/Q/What_is_the_average_mpg_of_a_tractor_trailer)).
So to go 400 miles, they're going to use 60-80 gallons of fuel. If you can
improve mileage to 9-10 MPG, they'll use 40-45 gallons of fuel - a reduction
in fuel consumption of 25-50% (or, an improvement in distance per gallon of
33-100%).

So if you swap-in electric vehicles for vehicles which consume the most fuel,
you'll see the biggest immediate impact. And transportation businesses (and
manufacturers aiming at the transportation sector) are going to be where the
biggest improvement always happen: they have the best economic incentive to
cut their costs, _and_ have the biggest pockets to do the research and
development to make it happen.

