Roundabouts

Current Design Standards

The existing traffic signal at the Ames Street intersection does not meet current design standards. It would be difficult to design a signalized intersection at this location to meet these standards due to the skew at which Ames Street intersects Jackson Boulevard and the curve in Jackson Boulevard at this location.

Traffic Study

The traffic study did not dictate a necessity for a signal at the Ames Street intersection. The traffic study did, however, dictate a necessity for a signal at Saint Joe Street, but this was determined to be inadvisable because the hill on the west leg of the intersection is too steep. So a roundabout at Ames Street was determined to be the best option for traffic flow.

The roundabout provides improved access to Jackson Boulevard from Ames Street, which is easily accessed from Saint Joe Street. A roundabout also eliminates the perpetual electrical costs associated with a new traffic signal.

Pros

The “pros” of roundabouts include:

• Increased traffic safety, decreasing fatal and severe injuring crashes, as there are fewer conflict points and slower speeds
• Decreased vehicle delays versus traffic signals or all-way stops
• Increased traffic calming, slowing vehicle speeds along the corridor
• Reduced costs without the ongoing electrical use of a signal

Cons

The “cons” of roundabouts include:

• More space is required, and the city would need to obtain additional right-of-way at the southeast corner of the Ames Street/Jackson Boulevard intersection
• Emergency vehicles are not given priority in a roundabout, as equal treatment is given to every approach
• Public education is required in areas where roundabouts are not the norm

Proposed Roundabout

Once people go through it and understand it once or twice, it’s easy. It’s very simple to get through. The proposed roundabout is in a relatively level area, with good sight distance. During the design phase, the engineers modeled how a WB-50 semi-trailer would be able to go all the way around the roundabout which shows that RVs, buses, fire trucks, etc, can also make it through the configuration.