Cars must change. Our detailed vehicle computer simulations have
shown that business-as-usual with incremental improvements in
the venerable gasoline-powered internal combustion engine (ICE)
will not be adequate to avoid the triple threats of greenhouse
gas emissions, oil dependence and urban air pollution. We
conclude that, to avoid massive environmental and energy
security disruptions, society must accelerate the process of
electrifying the transportation system. In one sense, we will be
turning back the clock over 100 years: in 1900 approximately 25%
of cars on the road were electric vehicles powered by batteries
(most were powered by steam engines, and another 25% or so by
gasoline internal combustion engines). Hybrids. The process of
partial re-electrification of the car fleet has already begun
with the introduction of hybrid electric vehicles (HEVs) that
rely on both a small gasoline-powered ICE and an electric motor
to drive the wheels. Plug-in Hybrids. The next step in the
electrification evolution is