Notes
∗This study was funded by research grants provided by the Rutgers Research Council, New Brunswick, N. J., 1973, the New Jersey State Department of Health, and the Department of Health and Welfare, Newark, N. J.
We would further like to acknowledge the assistance of Edwards and Kelcy, Inc., Newark, N. J. and the New Jersey Department of Transportation for use of unpublished vehicle density data. Further appreciation is expressed to Dr. Marvin Lavenhar and Dr. Donald B. Louria, Department of Preventive Medicine and Community Health, College of Medicine and Dentistry of New Jersey, Newark, N. J.