When Iowa's motor-fuel tax increased by 10 cents a gallon on March 1, it represented a road that was both brave and opportunistic.

It was also stupid, for two key reasons: Raising the gas tax doesn't fully address the funding need for critical road improvements, and over time it will provide less and less money while road-construction costs continue to increase.

Despite that, the hike was still brave, because raising taxes is never popular among voters - especially when they feel the pain every time they visit the gas pump. The Des Moines Register has polled Iowans about a gas-tax hike for the past five years. While the amount of the hike in the question has varied over the years, opposition to an increase was 70 percent in 2011. Opposition has eroded since then, but it was still 58 percent in February 2014.

Which leads us to opportunistic. Mirroring national trends, from July 2014 to early 2015 gas prices dropped from more than $3.50 per gallon in the Quad Cities and Des Moines to under $2, according to GasBuddy.com.

Prices have risen since then but are still more than a dollar cheaper than in mid-2014, so legislators saw a window of opportunity. The February 2015 Des Moines Register poll found 48 percent support for a 10-cent gas-tax hike and only 50 percent opposition - and the cost of fuel was certainly a factor in that shift.

The timing was great in political terms, too, just after a statewide-election cycle. The problem of deteriorating roads and bridges - and the choice for a solution - had been on the table since late 2011, but there's nothing like the longest period of time before an election to spur legislators into unpopular action.