What is hypermiling, from a traffic safety standpoint?

It is definitely NOT about drafting trucks, or turning one's car
completely off at highway speeds, or poking along and blocking
traffic -- despite what certain uninformed and misguided publicity
people at AAA and some other organizations would have us believe.

Hypermiling is about total concentration and precise, smooth control
of a vehicle.  The primary effects are minized fuel consumption and
increased safety.  When a hypermiler is out traveling on the roads,
attaining high efficiency is merely part of what's going on -- the
entire process becomes an integrated whole, a flowing union between
human and machine and the surrounding environment.  It is also the
willingness of a driver to create a set of efficient running
conditions and wait for the results, rather than be lured into the
false instant-gratification trap that has become so common.

In this state of awareness I stay 100% focused on the task of
DRIVING, keeping track of everything in front of me, behind me, to
the sides, and what's transiting the blind spots.  It is a highly
predictive process, in which I'm watching relative rates of other
vehicles fore and aft, what lane they're in and figuring where
they're likely to be in the next ten seconds, who's heading in from
an on-ramp or side street and how fast and bunched-up they are, and
what the terrain is doing up ahead past the merge point ... and at
the same time, watching my RPM and engine load and speed and hybrid
battery current and altitude [yes, altitude -- it matters!] and
calculating the best control change to adapt to all of that input
with as little "lurch" as possible.  I also determine what I can
about the attitude of nearby drivers based on actions, facial
expressions, or any other kinesthetic language I can read from the
vehicles or the people in them, and take that into account.  With
practice and attention, one can obtain an astonishing amount of
information just from how the nose of someone else's car moves. 
There are even more subtle observations most people would never
think about, such as soft-looking tires on another car, which also
contribute to the equation and the possibilities of what could
happen in the immediate future.

It's a constant and comprehensive situational analysis.

This is my ONLY job when I'm on the road.  Anything extraneous such
as a phone or coffee or radio would detract from that, which is for
the most part unacceptable.  Any distraction absorbs some of that
essential mental bandwidth, and coming at the wrong moment that could
be fatal.  Some minor distractions are inevitable for anyone on the
road but I strive to minimize those, leaving the stereo off and the
phone put away, and while the coffee is an important part of my own
personal road-trip fuel it rides in a covered mug with a straw that
eliminates any risk of spilling or losing my sightline to what's ahead.

And all this without cruise control, preferring to lock my right foot
into known "sweet spot" operational ranges for the car's engine and
drivetrain and tweak that up and down based on what's ahead.

The primary means of risk-reduction and the key to making this all
work is DISTANCE between vehicles, which allows the time and visibility
to make the correct responses in a non-abrupt fashion.  Abruptness
coupled with no reaction leeway is what kills.  Generous following
distance is step 1 and the easiest for any driver to establish by
simply not trying to go faster than a car ahead.  Because of traffic
patterns it isn't always possible to maintain the space cushion in
the other directions, particularly to the rear, but the hypermiling
community evolves techniques both active and passive to deal with
that too.  Part of safe, efficient driving is always trying to
re-establish that generous space when something impinges on it.
Obviously, any sort of aerodynamic drafting would be completely at
odds with that goal.

This style of driving implies an understanding of the physics in play,
never losing sight of the fact that all vehicles are large heavy
objects and it takes a lot of energy to get them moving and stopped
again.  Doing so efficiently yet smoothly in changing traffic conditions
is an elegant blend of art and science, and as complex as it may begin
to sound on paper it is almost paradoxically a much more relaxing,
unhurried way to drive than what we usually see on today's roads.
And destinations are reached in pretty much the same timeframe as by
those who feel the need to be aggressive and threatening to other
road users, proving time and again that the self-important illusion
of being in a hurry gains nothing but vastly increased risk.  The
bottom line is that hypermilers are hands-down the safest drivers
out there.

_H*  080925