Grimes Mayor Tom Armstrong has decided not to seek re-election after 16 years in the position. Armstrong, who is chairman of the Des Moines Area Metropolitan Planning Organization, noted his accomplishments in a statement, suggesting it was time to move on: “I am proud to say that the community has accomplished all the goals that I had when I first ran for office, and many more that I did not envision at the time.” The city grew to 12,000 residents from 5,000 in that period, and property valuations rose to $500 million from $150 million.