Two-lane roads used mostly by traffic heading to and from local homes and businesses are expected to get a lot busier when Interstate 69 is finished.

The roads, which include State Road 144, Smith Valley Road, Old State Road 37 and County Line Road, could see two or three times as many vehicles per day with traffic entering or exiting the interstate, or trying to get around it once other local roads dead end.

The issue is one local officials have been discussing for decades and have started planning for in recent years. But what exactly will be done to address the increased traffic hasn’t yet been decided.

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Three Johnson County roads — Smith Valley Road, County Line Road and State Road 144 — are expected to be impacted the most when I-69 is built along the last section from Martinsville to Indianapolis, according to a study by the Indiana Department of Transportation.

Each of those roads is getting an interchange, and according to the state study, all are expected to have a significant increase in traffic east of the interstate.

For example, on State Road 144, east of the interstate, daily traffic will increase more than 300 percent — from 5,100 vehicles in 2010 to 18,300 in 2045 after I-69 is built. Smith Valley Road’s traffic would more than double, from 9,900 vehicles to 21,100. And on County Line Road, daily traffic would also more than double, from 10,200 in 2010 to 22,300, according to the study.

If the interstate weren’t built, traffic was not estimated to increase nearly as much, the study showed. For example, on State Road 144, if I-69 were not built, traffic is expected to increase from 5,100 vehicles per day to 8,400 in 2045, according to the study.

To meet that expected demand due to I-69, local officials are in the beginning stages of planning road improvements.

Johnson County and Bargersville are paying $158,000 for a consultant to study current and future traffic patterns on most of the major routes through the Center Grove area, which will help prioritize road improvements. The study is expected to be finished by the middle of the year.

The study will gather the current traffic counts of the primary roads through the Center Grove area and Bargersville with an emphasis on key north-south and east-west routes that will see major changes to their traffic patterns. The main question is whether the roads can handle the projected traffic increase.

That answer is expected to be no, and having specific studies and data to back up those assessments gives the county a better chance when applying for state or federal grants to pay for the projects, officials have said.

At the same time, not all roads are expected to have an increase in traffic, according to the Indiana Department of Transportation study.

For some routes, the new interstate will take away some traffic, improving congestion issues. For example, Interstate 65 will see slightly less traffic than it would have in 2045 without the interstate. U.S. 31 on the southside would actually have a slight decrease in traffic in future years.

But U.S. 31, south of County Line Road, still would have an overall increase in traffic, though slightly less than what was projected for 2045 without I-69, the study said.

State Road 135, however, is not expected to see an improvement. Traffic levels are expected to continue to rise, leading to more congestion and a lower rating for traffic flow from the state, the study said.

But that would have happened with or without I-69 due to population growth, the study said.

By the numbers

Here is a look at how daily traffic counts are expected to change by 2045 if Interstate 69 is built and if it wasn’t:

Local roads

State Road 144, east of I-69

2010 count: 5,100

2045 without I-69: 8,400

2045 with I-69: 18,300

Smith Valley Road, east of I-69

2010: 9,900

2045 without I-69: 9,700

2045 with I-69: 21,100

County Line Road, east of I-69

2010: 10,200

2045 without I-69: 12,400

2045 with I-69: 22,300

Mullinix Road, south of Smith Valley Road

2010: 2,900

2045 without I-69: 4,200

2045 with I-69: 9,500

Old State Road 37, south of State Road 144

2010: 1,800

2045 without I-69: 1,900

2045 with I-69: 7,800

Sections of State Road 37/I-69

State Road 144 to Smith Valley Road

2010: 29,400

2045 without I-69: 43,000

2045 with I-69: 55,100

Smith Valley Road to County Line Road

2010: 27,700

2045 without I-69: 38,700

2045 with I-69: 65,000

SOURCE: Indiana Department of Transportation

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Annie Goeller is managing editor of the Daily Journal. She can be reached at agoeller@dailyjournal.net or 317-736-2718.