Modifications completed last year at three traffic roundabouts in Hilliard have resulted in fewer accidents at those locations, according to data collected by the city.

With a single exception, the number of reported accidents each month at each roundabout has declined since the modifications were completed last summer at the Main Street roundabouts at Cemetery and Scioto Darby roads and in January at Britton Parkway and Davidson Road, said Letty Schamp, the city’s deputy engineer.

“The modifications did what was intended,” Schamp said.

She said temporary modifications made at Main Street and Scioto Darby Road will be made permanent next year after proving to be successful.

The “triangle” roundabouts on Main Street at Cemetery and Scioto Darby roads each opened in 2011.

An increase in the number of reported accidents was expected as drivers acclimated, but the figures did not level off in the ensuing years, prompting city officials to take a closer look, Schamp said.

A report released by the Mid-Ohio Regional Planning Commission in 2016 showed the roundabout at Main Street and Cemetery Road had 233 reported accidents from 2013 through 2015, the most of any intersection in Hilliard. It was followed by Main Street and Cemetery Road, with 141 reported accidents in the same three-year span.

Based on the reports, Hilliard approved a $160,000 contract with Burgess & Niple, the same engineering and architecture firm that designed the roundabouts, to modify them to reduce the accident rate.

With those results in hand, Hilliard contracted with Strawser Paving Co. for $544,000 to make modifications to both Main Street roundabouts.

The changes to the roundabout at Britton Parkway and Davidson Road were made as part of a package of other projects within the city’s annual capital-improvements budget, Schamp said.

The modifications included the placement of signs with red LEDs in the center island of the roundabout at Main Street and Cemetery Road, she said.

Raised crosswalks, resurfacing and overhead lane-control signs were included in the project.

The resurfacing provides better visibility for the new pavement markings, Schamp said, and the raised crosswalks have slowed vehicle speeds and improved pedestrian safety.

Entry and exit velocity is slower as a result of the modifications, she said.

At Main Street and Scioto Darby Road, the roundabout was reshaped, as engineers concluded a “skewed” angle was a contributing factor in crashes, Schamp said.

In an effort to “reshape” the roundabout at Main Street and Scioto Darby Road into more of a circle than an oval, the city built temporary curbs in the roundabout, she said.

“The improvements at Main Street and Scioto Darby have been effective and successful,” Schamp said.

The temporary curbs the city used will be replaced with permanent modifications, Schamp said, and new pavement markings and overhead signs will be added next year.

The city has obtained a federal grant of $500,000, administered by the Ohio Department of Transportation, to fund the improvements, Schamp said.

Last year, at Main Street and Scioto Darby Road, two accidents were reported in both August and September. None were reported in October and November, and one in each month were reported from December to March.

At least three accidents, and as many as six, were reported each month from July 2018 to May 2019.

At Main Street and Cemetery Road, 10 accidents were reported in September 2019, the month after the improvements were completed. That figure decreased to four in October and one in November.

The average number of accidents was seven each month from July 2018 to June 2019, according to data provided by the city.

Schamp said accident rates in March and moving forward are affected by reduced traffic volumes related to the state’s stay-at-home orders to limit the spread of the COVID-19 coronavirus.

Although Hilliard does not track the precise number of vehicles entering the roundabouts – only the number of reported crashes – the city can generalize an accident rate based on counts at Cemetery and Lacon roads nearby, Schamp said. Recent improvements at that intersection include a camera that counts every vehicle passing through.

“Traffic volume is down,” Schamp said.

According to the city’s data, almost 35,000 cars passed the intersection March 13.

That total decreased to a little more than 23,000 the following day and fewer than 13,000 vehicles March 29.

Meanwhile, the improved intersections are a benefit to motorists, residents and the city’s corporations and small businesses, said Libby Gierach, president and CEO of the Hilliard Area Chamber of Commerce.

“It is easier for our residents to access our businesses and parks with the improved modifications to the roundabouts on Main Street,” Gierach said. “People have become more familiar on how to navigate them to get to their destination.”