INDOT introduces flashing yellow arrows around Putnam County

Banner Graphic/Jared Jernagan With the newly-installed flashing yellow arrow signal overhead, a motorist takes advantage of a break in traffic to turn left from Veterans Memorial Highway onto U.S. 231 on the city’s South Side Friday morning.

Intersections around Greencastle and Putnam County have been busy this week with utility work, as Indiana Department of Transportation crews introduce a new statewide safety initiative to Putnam County.

With the addition of flashing yellow arrows for designated left turn lanes, INDOT officials hope to make right-of-way more explicitly clear to motorists.

“The flashing yellow arrows are part of a general INDOT initiative, which is being phased in area by area in the Crawfordsville District,” spokesman Debbie Calder said. “The most notable change to these new traffic signals will be the addition of a flashing yellow arrow.

“Flashing yellow arrow signals allow left-turning traffic to yield the right-of-way to oncoming traffic and pedestrians and turn when a suitable gap is available. This type of signal improves intersection efficiency by using cross-traffic gaps to allow more left turns.”

When waiting in a dedicated left-turn lane, motorists may first see a flashing yellow arrow, depending upon signal phasing.

Should there not be suitable gaps in oncoming through traffic and sensors detect cars waiting to turn left, the flashing yellow arrow could change to a steady green arrow. This would stop oncoming traffic, allowing a protected left turn for drivers.

In Putnam County, flashing yellow arrows have been installed or soon will be in five locations:

• U.S. 231 and U.S. 36

• U.S. 231 (Bloomington Street) and SR 240 (Veterans Memorial Highway)

• SR 240 (Veterans Highway) and Old SR 240 (Indianapolis Road)

• SR 240 and Calbert Way (Greencastle Walmart entrance)

• U.S. 231 and County Road 925 South/Stardust Road

INDOT cites research that the flashing yellow indication is more readily understood by motorists to mean “proceed after yielding to opposing traffic,” as compared to the circular green indication.

Flashing yellow arrows enable signal efficiency to be greatly improved in several ways.

Flashing yellow arrows allow for a mix and match of protected left turn movements (left turners can only proceed during the green arrow), permissive left turn movements (left turners can only proceed after yielding) and protected-permissive left turn movements (left turners get a green arrow followed by a flashing yellow arrow), where the most appropriate of the three is chosen during different times of day.

For example, during morning and evening rush hour, only protected left turn movements are allowed because it is too busy to safely turn left after yielding. During the off-peak times in the middle of the day, protected-permissive left turn movements are allowed. During the middle of the night, only permissive left turn movements are allowed to avoid unnecessarily giving thru traffic a red light.