Regular readers here will remember that I've pointed to and occasionally discussed the Blade Runner road/rail truck concept. Well, it came up again in an e-mail discussion the other day (the fruits of which might appear elsewhere). I pointed out that even a doubling of truck fuel economy over the next 14 years would only cut total consumption by 34% if road mileage continues to increase by even 2% per year; if we could double economy AND switch 60% of mileage to modes which don't burn any fuel, we could increase the savings to 74% *. I got the following response, which I should have anticipated:
> The question is, CAN we move 60% of that mileage to modes
> which run on electricity in 14 years?
Not having an answer ready meant that I hadn't done my homework. Better late than never; I went directly to the BTS1 to check it out. Here's what I came back with:
In 2003, there were 3,974,1072 miles of highway in the USA, of which about 46,500 miles was interstates3. The total urban free/expressways (interstates and other) came to 24330 miles; rural interstates are another 32048 miles (total 56378 for all freeways), and other rural arterials come to 97039 miles.
The same year, combination trucks (semi-trucks and vehicles with trailers) travelled 140,160 million miles4. I could not find the mileage breakdown for this category.
Commercial trucking in general seems to have more detailed statistics available5. Commercial trucks travelled 215,884 million miles in 2003; we're looking for 60% of that, or about 130,000 million vehicle-miles. Urban and rural interstates accounted for 86,692 million vehicle-miles (almost 2/3 of the target), leaving about 43,000 to go. Other urban streets account for 58,830 million vehicle-miles, but we probably can't convert lanes of surface roads to electrified rail (save for dual-use, like trolley cars?) so it's questionable how much of that could be electrified. On the other hand, short hauls away from an electrified artery could be driven on power from flywheels or batteries; this may not be hopeless. Rural arteries tend to be less heavily travelled (otherwise they wouldn't be rural) and do not account for as much fuel use per mile of road as urban ones.
Electrification of the urban arteries would be best for eliminating diesel emissions in densely populated areas. This is a two-fer.
It all comes down to money. Adding two lanes of electrified rail to all interstates and urban free/expressways means ~113,000 lane-miles of rail3; that covers about 40% of all truck vehicle-miles. Covering the most-travelled 50% of urban truck routes means another ~59,000 lane-miles of rail (plus overhead wires) in urban areas, getting at least half of the remaining 43,000 million vehicle-miles. Power from flywheels or batteries could make fuel-free, zero-emission jaunts from the main lines to destinations, maybe getting the balance. It would be close regardless.
This scheme would have a total of about 172,000 miles of rail. If we could build that out at 20,000 lane-miles per year we'd have it in about 8.5 years. There's almost 4 million miles of road in the total system3, and rebuilding it every 20 years means at least 200,000 miles of road (much of it 4- and 6-lane) per year. This looks feasible to start by 2010 and have finished by 2020, with time to spare. At $2.4 million per lane-mile, the capital cost would be about $270 billion or about $35 billion per year.
Note that this does not include the simple expedient of throwing rails back onto unused rights-of-way and running trucks on it.
"Combination trucks" burned about 27 billion gallons of fuel in 20036. 60% of this is 16.2 billion gallons. At $2.50 per gallon, it would cost $40.5 billion per year; substitution of electricity at 1.5 kWh/mile and 10 cents/kWh (including savings from lower rolling resistance of rail) would cost 19.5 billion dollars per year, for a gross savings of $21 billion/year for energy. The investment would pay off in about 14 years, not including lower expenditures for pollution control, health, and other external costs of petroleum consumption in general and diesel fuel in particular. If trucks other than "combination trucks" could use the rail/electric system it would pay off faster, and any increase in fuel prices would do the same.
Note that rail moved about 1/3 more ton-miles of freight in '03 than trucks did7, while consuming only 3.8 billion gallons of fuel8 to trucks' almost 38 billion gallons9. The more we can make trucks like rail (and efficient as rail), the more we can ship without burning fuel.
*
A 2% per year increase in vehicle-miles compounded over 14 years comes to 32%, or 132% of the original. If fuel per mile is cut in half, fuel consumption falls to 66%, or a 34% decrease. Slashing another 60% off the fuel consumption by replacement with e.g. electricity cuts the net
fuel consumption to 26.4% of the original, or a 74% decrease despite a 32% increase in vehicle-miles.
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[1]
http://www.bts.gov/publications/national_transportation_statistics/2005/index.html
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[2]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_01_01.html
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[3]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_01_05.html
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[4]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_01_32.html
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[5]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_truck_profile.html
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[6]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_04_05.html
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[7]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_01_46b.html
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[8]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_04_17.html
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[9]
http://www.bts.gov/publications/national_transportation_statistics/2005/html/table_04_05.html
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