From Worldchanging:
Sightline Institute’s blog The Daily Score recently noted that people always prefer streetcars and other light rail to buses. They aren’t just being subjective, either–history backs them up. In 2001 the Denver Business Journal wrote of new light rail systems being mobbed in Denver, Dallas, Salt Lake City and St. Louis because they were so much more popular than forecasted, saying “In Dallas, ridership on a new rail line was three times greater than ridership on an express bus that used the same route” and quoting government officials who were realizing “How people respond to rail is different than how they respond to bus”.
So, why the mysterious preference for light rail? Two words: Better design.