The combination of GPS (global
positioning system) satellites, high-density computer storage of map data,
electronic compass, synthetic speech synthesis, and computer-graphic displays
allows cars and trucks to know where they are located on the Earth to within
100 m or less, and can guide a driver to a programmed destination by a
combination of a map display and speech. Some human factor challenges are in
deciding how to configure the map (how much detail to present, whether to make
the map northup with a moving dot representing one’s own vehicle position or
current-heading-up and rapidly changing with every turn). The computer graphics
can also be used to show what turns to anticipate and which lane to get in.
Synthetic speech can reinforce these turn anticipations, can caution the driver
if he is perceived to be headed in the wrong direction or off course, and can
even guide him or her how to get back on course. An interesting question is
what the computer should say in each situation to get the driver’s attention, to
be understood quickly and unambiguously but without being an annoyance. Another
question is whether or not such systems will distract the driver’s attention
from the primary tasks, thereby reducing safety. The major vehicle
manufacturers have developed such systems, they have been evaluated for
reliability and human use, and they are beginning to be marketed in the United
States, Europe, and
Japan.