Wednesday, July 31, 2013

Public transport, & the personal auto

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According to the US Transportation Energy Data Book as quoted in Wikipedia, the following are the energy efficiencies of various modes of transport:

Intercity Rail - 1.6 (Mega Joules)/(passenger-kilometer)
Commuter Rail - 1.84 MJ/p-k
Air - 1.85 MJ/p-k
Cars (1.55 passengers/car) - 2.32 MJ/p-k
Buses - 2.78 MJ/p-k

The thing to note is that cars are not THAT bad compared to the other methods.  What is more, the average fuel economy is mandated to double to 54 mpg (about a current Prius C's fuel economy) in a few years.  If nothing else changes that will halve the energy consumption for the average car to 1.16 MJ/p-k making it much BETTER in energy efficiency than anything else, including public transport.

But other things can change.  These car sharing programs like Zip-Car could really take off so people could commute 4/car instead of 1.5/car with self-driving cars and coordinated real-time source-destination matching programs.  

In addition, bio-fuel is fast becoming a reality with commercial feasibility making cars carbon neutral:

And of course electric cars powered by small electric currents embedded in the road and fed by solar panels could make it all clean energy with no charging issue.

Driving in the US may have actually peaked in 2004 meaning more people are using public transport or biking or walking.  

There is still the space factor.  Cars take up a lot of space but so do buses and trains.  Even in cities like SF it can get hard to get public buses to get across town so cars are going to be needed even in cities.  Cars like the Smart Car are making "small = cool" so even space issues can change.

So, cars will evolve to become one part of the transportation mix and possibly the most energy efficient, earth-friendly mode.

No one has yet told me why I still see the "Cars Bad!  Buses/Trains Good!" attitude.  Since no one else has addressed it I will hazard a guess that it is left over from the early 1970's when cars REALLY were bad.  The average car sold in 1971 got 13 MPG and one popular Pontiac got 9 MPG!  That was when repeated oil shocks over the 70's gave us stagflation but forced congress to mandate a doubling of fuel economy from 13 mpg to 27 mpg.

Old opinions die hard and I suspect many in the environmental leadership may have formed their opinions then and not noticed that things have changed while young environmentalists just accept it as gospel.

So, can we get away from the anti-car thing?  If friends come to visit, I would like them to be able to park.


  1. Lots of good information in your posting, I would like to tweet your blog post so I can visit again in the near future.

    Auto transport

  2. Please do - I am honored you think it worthwhile.