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The color-coded graphic on this page depicts average historical traffic speeds during 15-minute intervals on Interstate 235. The data used to calculate the averages were collected between 2006 and 2009 – during peak usage times between Tuesday and Thursday – from sensors at 16 locations along the freeway by the Iowa Department of Transportation.

Our graphic specifically shows data during the morning commute on I-235 from the western suburbs to the eastern end of I-235 at the I-35/80 East Mixmaster interchange and the evening commute for those same drivers going back to the western suburbs.

To utilize the graphic for your own advantage, pick a time that you usually get on I-235 in the morning or evening. Follow the column all the way to the bottom and you’ll find the average speed that you’ll be traveling along I-235 and the average time it will take you to travel the entire length of the 13.3-mile freeway or the time it takes to travel about 8 miles between the West Mixmaster and downtown.

Your absolute best option – if your bosses will allow it – is to get on I-235 at about 7 a.m. and go home at about 4 p.m. Over the course of time, you could save three minutes per day on average. That might not sound like much, but translate that over the course of 10 years, and you can save upwards of five days of your life.

The Des Moines Area Metropolitan Planning Organization (MPO) compiled the data as part of its efforts to identify locations that consistently show up as having speeds below 55 miles per hour, the lower of the freeway’s two posted speed limits.

Adam Noelting, the MPO’s principal transportation planner, said the organization hopes to use the data in its congestion management document so that it can identify potential solutions to relieve congestion points and then in the future see if the solutions worked.

Noelting said it is a positive that fewer than half of the data points are under the 55 mph mark, but said it is important to note that an actual driver’s experience with speed might be much slower – there are times when things are at a standstill – or might be much faster during that 15-minute interval. He said the MPO is identifying ways to account for that deficiency in its data.

Not shown in our graphic are speeds and travel times for those commuters going the opposite direction. Don’t worry; only 8 percent of the data points had average speeds below 55 mph.