Workers are set to break ground Monday on a 70-foot electronic highway billboard that would permanently constrict traffic on a Jefferson Park side street, despite widespread opposition from neighbors.City officials announced late last month that they were taking a third shot at erecting the billboard, following through on a 2012 deal allowing advertising company JCDecaux to build 63 such signs along city expressways. The most recent plan would extend the billboard into the curving two-way intersection of Lamon and Wilson, narrowing the street in front of the Mayfair Pumping Station to a single lane and directing cars to take turns traveling in each direction.

In July 2015, the first time workers tried to build the glowing sign, Ald. John Arena parked his car to block construction, saying his office not been notified of the work. That project would have blocked the street entirely, turning both Wilson and Lamon into dead-end streets.

The alderman shot down a second proposal in summer 2016, when the city’s transportation and finance departments proposed turning the slip into a one-way street.

But the alternating two-way design now on the books is the best compromise neighbors can expect, the alderman told the Sun-Times.

“If someone can come to me with a solution that keeps the whole roadway open while honoring the city’s contractual obligation . . . and all the other legal restrictions, I’ll park my car out there again tomorrow morning,” Arena said. “But we have to move something forward based on the parameters that are in front of me.”

Arena was one of the few aldermen who voted against the 2012 ordinance.

Neighbors excoriated the plan during a public meeting organized by Arena on Wednesday night, according to multiple people who attended. Speakers predicted constant gridlock on the street, which locals often use to bypass traffic on the Kennedy Expressway during rush hours.

John Caravette, whose solar panel installation company Earth Wind & Solar Energy would sit in the billboard’s shadow, said the narrower street would be a “nightmare” for trucks making deliveries outside his business at 4831 W. Wilson.

“Imagine what it’s going to be like when a truck has to make a U-turn here, and there’s a long line of cars waiting in the street,” Caravette said. “Honestly, this is probably the worst place they could possibly put this thing.”

But city officials said a patchwork of federal laws, city codes and special circumstances make their planned site the only place the billboard can go.

The U.S. Highway Beautification Act of 1964 precludes the sign from being within 500 feet of another billboard on the same side of the highway, and city code forbids it from being within 94 feet of a residential home.

The city’s finance department had originally planned to build in a grassy patch in front of the pumping station, until they found it would tamper with underground water lines.

Chris Stegh, who lives in the 4700 block of North Laporte, asked officials at meeting if the city could seek a variance to the 1964 law.

“These other billboards they have to build away from aren’t even in the same sight line, but meanwhile you have another one right across the Kennedy, 350 feet away,” Stegh said. “So why can’t the parties involved come up with an exception to the 500-foot limit?”

Arena countered that looking for ways around the federal law is “not a precedent we want to set,” as it could encourage advertisers to try and squeeze signs closer together than currently allowed.

After the latest plan was announced last month, Stegh posted an online survey soliciting feedback from hundreds of neighbors; many said restricting traffic would fill the street with cars and render it unsafe for pedestrians.

Finance department spokeswoman Kristen Cabanban said city officials “do not anticipate” that the new street design will worsen traffic, adding that the plan is “intended to improve safety.”

“The new stop sign will require drivers to slow, stop and wait for conflicting traffic to clear the intersection before proceeding through,” Cabanban said.

Construction is scheduled to wrap up by Aug. 6, officials said.