There is a growing social interest in developing vision-based vehicle
guidance systems for improving traffic safety and efficiency and the
environment. Ex- amples of vision-based vehicle guidance systems include
collision warning systems, steering control systems for tracking painted
lane marks, and speed control systems for preventing rear-end
collisions. Like other guidance systems for aircraft and trains, these
systems are ex- pected to increase traffic safety significantly. For
example, safety improve- ments of aircraft landing processes after the
introduction of automatic guidance systems have been reported to be 100
times better than prior to installment. Although the safety of human
lives is beyond price, the cost for automatic guidance could be
compensated by decreased insurance costs. It is becoming more important
to increase traffic safety by decreasing the human driver's load in our
society, especially with an increasing population of senior people who
continue to drive. The second potential social benefit is the
improvement of traffic efficiency by decreasing the spacing between
vehicles without sacrificing safety. It is reported, for example, that
four times the efficiency is expected if the spacing between cars is
controlled automatically at 90 cm with a speed of 100 kmjh compared to
today's typical manual driving. Although there are a lot of tech- nical,
psychological, and social issues to be solved before realizing the high-
density jhigh-speed traffic systems described here, highly efficient
highways are becoming more important because of increasing traffic
congestion.