1. GIS Analyst, URS, Morrisville, NC 27560.
2. Dept. of Civil Engineering, North Carolina State Univ., NCSU Campus, Box 7908, Raleigh, NC 27695 (corresponding author).
3. North Carolina Dept. of Transportation, Geographic Information System Unit, Statewide Planning Branch, 3401 Carl Sandburg Ct., Raleigh, NC 27610.
4. North Carolina Department of Transportation, Geographic Information System Unit, Statewide Planning Branch, 3401 Carl Sandburg Ct., Raleigh, NC 27610.