Since this and other restrictions were lifted towards
the end of the century, our commuter hierarchy has been turned on its head.
No matter where we go (in cities or in countryside) it
is hard to escape the realisation that the car is king. Roads are designed
primarily for the private motorcar. Footpaths are shunted off to the side, if
they exist at all. Cycleways are often an after-thought.
The hierarchy nowadays is clearly the car is at the
top, followed by the cyclist, with pedestrians at the bottom of the pyramid of
privilege and right-of-way.
Yet, if we think in terms of vulnerability then,
surely, we have the hierarchy upside-down.
Consider a collision between a private car and a
cyclist, or a private car and a pedestrian. We all know who is going to come
off worst.
The physics alone should tell us. Damage done in a
collision can be attributed in big part to the kinetic energy (KE) of the
colliding bodies. KE is easily computed if we know the mass (m) of the body and
the velocity (v) at which it is travelling.1 Kinetic energy is
measured in Joules. The greater the number of Joules, the greater the energy.
Consider these measurements:
The average mass (weight) of a private car is 1300 kg.
Suppose a car is travelling at 50 km per hour (13.9 metres per second) then the
kinetic energy of the vehicle is approximately 125,000 Joules (J). Travelling
at 30 k.p.h. (8.3 metres per second (m.s.)) turns out to be approximately
45,200 J.
A male cyclist, on the other hand, weighing 87 kg (the
average weight for an adult Australian male) and cycling at 20 k.p.h. has a
kinetic energy of approximately 1,400 J. At 25 k.p.h. the kinetic energy is over
2,200 J. For an average Australian woman, the equivalent kinetic energy is
1,200 J and 1,900 J respectively.2
Now, consider a pedestrian, walking at 5.5 k.p.h. (1.6
metres per second). The kinetic energy of an average Australian male pedestrian
is about 110 J. For an average female pedestrian, the kinetic energy is about
90 J.
Damage
Imagine a car with a kinetic energy anywhere from
45,000 J to 125,000 J colliding with a cyclist with between 1,200 J and 2,200
J. Who is going to be damaged the greatest?
What about a pedestrian with kinetic energy of only
around 100 J?
Surely, if we are serious about lives, potential
damage, and harm, then we should be upending our commuter hierarchy. The car is
king does not make sense in terms of vulnerability.
It Doesn’t Make Sense in Other Ways
Nor does giving the private vehicle its high esteem
and privilege make sense in other ways.
The private vehicle is possibly the most environmentally
damaging piece of technology that an individual can own. We have known for
decades the damage from exhaust fumes. We know too the damage that the road
network has on local ecosystems, as well as the sheer amount of land given over
to parking and roading that our addiction to the motor-vehicle requires.
Plus, our addiction to the private vehicle as a means
of transport has seen our weights rise, so that now obesity rates in some parts
of the world are at epidemic levels. We have sacrificed well-being for comfort.
Should we not be thinking it is time to turn our commuter hierarchy up the other way, so that we privilege the most vulnerable?
Time to bring back the red flag.
Notes:
1. The formula for those interested is KE = ½ mv2
2. Using an average bicycle weight of 8 kg. The kinetic
energy will vary from person to person. Significantly, for a child the kinetic
energy is much less.
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