\begin{table}
\figuremargin{
%\margintab{
\begin{tabular}{cl}\toprule
\multicolumn{2}{c}{{ Energy per distance}}\\
\multicolumn{2}{c}{{ car doing 33\,mpg (12\,km\ per\ litre)}} \\ \midrule
occupants \\
1
& 80\,\kWh\ per 100 person-km\\
4 & 20\,\kWh\ per 100 person-km\\%
\bottomrule
\end{tabular}
}{
\caption[a]{
Facts worth remembering:
passenger transport efficiencies.\index{transport!efficiency!car}
%% 33 miles per imperial gallon is
%% 12\,km\ \per\ \litre.%%% 11.68
}\label{tabCar80}
}
\end{table}
To convert between \ind{transport energy efficiency}
in kWh per 100\,km
and \ind{fuel efficiency} in litres per 100\,km, I
use 10\,\kWh\,per\,litre for petrol and 11\,kWh\,per\,litre for diesel.
% \newpage
\amarginfig{t}{
\begin{center}
\begin{tabular}{c}
%\mbox{\epsfxsize=50mm\epsfbox{../../images/butter/floats1.eps}} \\
\mbox{\epsfxsize=35mm\epsfbox{../../images/butter/floats2.eps}} \\
\mbox{\epsfxsize=35mm\epsfbox{../../images/butter/floats3.eps}} \\
\end{tabular}
\end{center}
\caption[a]{
\protect\pref{butter}: Butter floats.
}
}
\begin{tabular}{ll} \toprule
$C_{\rm{rr}}$ & wheel \\
\midrule
0.001--0.0025 & train steel on steel \\
0.005 & tram-rails \\
0.005 & bicycle tire \\
%% up to 0.012 with some tyres on Trike at low temp
%% down to 0.004 at 70F.
%% I'd say 004 to 009 is the range to use. for bicycle.
0.006 & best rubber tyres on a smooth road \\
0.010--0.015 & car tyres on concrete \\
0.020 & car tyres on stone \\
0.030 & car tyres on asphalt\\
\bottomrule
\end{tabular}
Rolling resistance --
Wheel flex, friction losses in the wheel bearings, shaking and
vibration of both the roadbed and the vehicle (including energy
absorbed by the vehicle's shock absorbers), and slight sliding of the
wheels on the pavement/rail.
For example a car with 1000\,kg on asphalt
will need a force of 300\,N for rolling.
Often the rolling resistance is small compared with
the two main forms of energy consumption -- brakes and air-swirling.
The force required to deal with drag (air-swirling) scales as
speed squared; the forces associated with rolling resistance
are either simple constants -- independent of speed -- or else
they scale linearly with the speed.
of those driving, distances are
a=[
31144 39707 39613 42434 36804
]
b=[
1 3.5 7.5 15 50
]
average distance driven TO WORK is about 16km (for car) ->> 32km round trip is average
scotland average distance to work for all is 5.3 miles
Dundee and Aberdeen commuters travel 22 miles to work
glasgow commuters, 10.6 miles
So 44 miles is reasonable round trip figure
Which is 71km.
This is {\em not\/} my estimate of the distance
travelled by an `average' British person\label{pageAveragecar} --
as I said on page \pageref{typicalaffluent},
I aim to estimate the consumption of a ``typical
moderately-affluent person'' -- the consumption that many people
aspire to.
Some people don't drive much. I want to estimate the energy
consumed by someone who chooses to drive, rather than depersonalise
the answer by reporting the average, which mixes together the drivers
and non-drivers.
If you'd prefer to use different figures, feel free.
For example, if you know that you drive 20\,000\,\km\ per year,
then that's 55\,\km\ per day; so you can take my 100\,km-per-day answer and
halve it.