Agree - sidewalks are important to getting more people walking. Check this out:

Sidewalks result in 15-50% increase in physical activity

http://newscenter.sdsu.edu/sdsu_newscenter/news.aspx?s=71384

According to a San Diego State University study published in this month’s American Journal of Preventative Medicine, the biggest single factor influencing physical activity around the world is accessibility to sidewalks.

Researchers looked at data from 11,541 survey participants in 11 countries, which included the United States, Lithuania, Brazil, Sweden and Japan. Those individuals who reported living in a city neighborhood with easy access to sidewalks were 15-50 percent more likely to get moderate-to vigorous activity at least five days a week for at least 30 minutes each day.

Sallis and his fellow researchers also recently completed a long-term study focusing on communities in the United States which also found that people living in high-walkable communities got substantially more exercise and were less likely to be overweight than those living in low-walkable areas.