In a Portland, Oregon study of elderly women living alone, urban form with mixed services and good pedestrian access was associated with more walking. Additionally, elderly women in standard suburban residencies were nearly twice as likely to drive as their urban counterparts.
Patterson, Patricia K., and Nancy J. Chapman. (2004). Urban Form and Older Residents’ Service Use, Walking, Driving, Quality of Life, and Neighborhood Satisfaction. American Journal of Health Promotion 19(1), 45-53.