The scoreboard at Heinz Field is 96 by 28 feet.

The portal of each of the Liberty Tunnels is 29 by 21 feet.

In between, at 60 feet wide by 20 feet tall, is the size of a planned electronic billboard that will sit on the face of the new bus station under construction at Grant Street and Liberty Avenue.

In other words, it's one big sign.

The Lamar Advertising lighted electronic display will start 32 feet above ground at the junction of the central business district, the Strip District and the Cultural District. That's at the eastern end of Grant Street, which is considered Downtown's main street, lined as it is with government offices and the city's most powerful corporate citizens. Years ago the city spent millions installing a brick roadway and planters, an effort to beautify Grant and transform it into a grand boulevard.

If a huge, lighted, moving advertising billboard is going to be parked at its terminus, that is the kind of decision that needs proper review.

But the heads of the city Urban Redevelopment Authority and the Zoning Department thought it could bypass the normal regulatory approval process. Pat Ford and Susan Tymoczko gave the Pittsburgh Parking Authority, which owns the building, permission for the 1,200-square-foot sign.

Complicated city zoning regulations indicate that Planning Commission and City Council hearings and approval are required even when signs are significantly smaller and lower than this one, or when exterior work will cost more than $50,000, which is less than this sign's price tag. The code makes some exceptions, but there's no evidence yet that this sign would fit them.

How can city administrators simply ignore regulations on the books? Mr. Ford and Ms. Tymoczko say they made a deal with Lamar in which the company agreed to take down six nearby billboards that totaled 1,400 square feet of ad space in exchange for this one 1,200-square-foot sign. Even if that's OK, it first deserves regulatory review.

Fortunately, City Council decided to look into the situation. The best way to determine whether this dramatic, prominent sign proposal conforms to the law is to give it careful public scrutiny in the city's normal review process.