Transportation Planner, Parsons Brinckerhoff, Seattle, WA, c. 2008; in 2008, Arnold had had over 20 years of experience in transportation planning.

Arnold gave the keynote speech, "Leveraging Information for Innovation: Spatial and Temporal Visualization of Complex Information," at the iEdge Conference 2008: Information: Crafting Our Future held on 04/02/2008, HUB, University of Washington, Seattle.

Arnold was an expert in creating new mapping concepts using GIS programs.