Billboard-sized digital signs that now tower over Interstate 670 will function as Ohio's largest traffic signals.

Ohio Department of Transportation contractors last week used cranes to mount nine digital signs on overhead trusses along I-670 between Downtown and I-270.

This fall, as drivers pass those trusses, the digital signs will show whether the state’s first SmartLane is open on I-670’s left shoulder. Most of the time, the lane will remain closed. But when traffic slows to a crawl, ODOT will be able to reduce the speed limit for all vehicles using I-670 and open the extra lane.

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The signs are 10 feet tall and up to 60 feet long. Together with trusses, they can weigh up to 110,000 pounds.

That means some of the signs can be as long as about four Honda Accords manufactured about 30 miles northwest of Columbus in Marysville. It would take 32 Accords, weighing in at about 3,400 pounds each, with some spare parts in their trunks to even the scales with the heaviest truss and sign.

And those super-sized 60-inch TV's you watch college football on every Saturday? The largest of ODOT’s digital signs covers about the same square-footage as 56 of those.

How do you swing a 110,000 pound sign into place? A really big crane and lots of manpower. This is the second of nine overhead signs for I-670 east... talk about massive! #SmartLane pic.twitter.com/IeL4pdXWp6

— ODOT Columbus (@ODOT_Columbus) August 6, 2019

Radar detectors that will register vehicle speeds on I-670 to ODOT’s traffic management center also are expected to be added to those trusses. ODOT also is installing more than 30 traffic cameras to monitor the SmartLane for obstructions such as trash and debris or disabled vehicles.

When average speed on I-670 dips below 50 mph, a traffic monitor will decide whether to open the lane, said Breanna Badanes, an ODOT spokeswoman. That typically will happen during the afternoon rush, but the lane also could be used when a crash bogs down traffic. Disabled vehicles and traffic enforcement still can pull over to the right shoulder.

“The software and equation is flexible so we can make adjustments as needed,” Badanes wrote in an email.

The digital screens will alert drivers when the SmartLane is open or closed. A red X will be used to tell them the SmartLane is closed or a green arrow to show that it’s open. If the lane is about to close, the digital sign will display a yellow indicator.

They also will display the reduced speed limit when the lane is open.

Badanes said crews are installing the new traffic cameras and connecting power to the signs this week.

The SmartLane and a new interchange from eastbound I-670 to I-270 are expected to be open in October. The total project cost is about $61 million, with most of that spent on the new interchange.

Construction crews still are working on the interchange, which will require eastbound I-670 drivers to decide earlier whether they want to exit onto northbound I-270 or use Route 161. Both exits will have their own ramps, with drivers already on northbound I-270 entering between the other two.

ODOT redesigned the ramps to reduce the amount of sudden breaking and weaving caused by drivers trying to move into the lane they need.

rrouan@dispatch.com

@RickRouan