An Iowa Department of Transportation report has indicated that the I-35/U.S. Highway 30 cloverleaf interchange has the highest crash rate of the six cloverleaf interchanges located within Iowa. Because of that high crash rate, the Iowa DOT is proposing improvements that could potentially lower the number of accidents at the interchange. Those improvements will be discussed at a public meeting that will begin at 5 p.m. on Feb. 16, at CrossRoad Baptist Church in Ames.
Mike Clayton, Iowa DOT district transportation planner, said the meeting will be open to the public so that any concerns can be addressed.
"It will be an open forum meeting, which means we’ll have layouts and displays of the project. Basically, we’re just there to answer any questions," Clayton said.
Currently, the interchange is designed as a full cloverleaf with short weaving segments between the loop ramps. According to a Iowa DOT report released in June of 2014 that attempts to justify the need for improvements in the area, the short weaving segments degrade traffic operations and safety between the loop ramps of the interchange.
The proposed improvements project would reconfigure the interchange to eliminate the short segments and improve the overall safety and traffic operations.
According to the report, the need for these types of improvements are going to continue to grow in importance because the number of drivers and the likelihood of accidents rise as the population in the area grows.
"The traffic’s increased over time. Back in the mid-60s, when I-35 was originally built, we probably had maybe 8,000 vehicles a day; now we’re around 40,000," Clayton said.
The report states that traffic in the area is expected to grow about 2 percent per year until the year 2038. According to a traffic flow map of Ames, in 2011 the average number of drivers per day on I-35 south of U.S. 30 was 38,800. If that number grows at the predicted rate, that means that 69,988 drivers will pass through that interchange on a daily basis by 2038.
That is a number that Clayton said could cause a large increase in the number of accidents happening at that site.
"There have always been accidents out there. If you put two cars on a road, you’re going to run into each other sooner or later," Clayton said.
To complete the report, the Iowa DOT looked the intersection’s crash data, compiled between 2008 and 2012. In that five-year period, there were 154 crashes in the interchange, with a single fatal crash recorded. Those numbers put the interchange above the statewide average for crash rates, which was evaluated as an intersection because the Iowa DOT maintains crash rate averages for intersections but not for interchanges.
According to the DOT, the average crash rate for intersections, with more than 25,000 vehicles entering per day, is 1.0 crash per million entering vehicles. The crash rate for the I-35/U.S. 30 interchange was found to be 1.47 crashes per million entering vehicles.
Of those crashes, 45 percent were found to have occurred in the short segments between ramps, according to the report.
With that information, the Iowa DOT has concluded that improvements should be made in the area to bring the interchange up to current standards. Those improvements can be found on the Iowa DOT’s website and public input on the project can be made at the Feb. 16 meeting.