Why would engineers restrict a main highway in both directions at a time? Why block off three miles while work is taking place on only part of the highway?

Kevin White, of Murrysville, asked those questions while raising what he called "an age-old complaint" about road construction procedures.

He is a regular driver of Route 28, or the Allegheny Valley Expressway, where PennDOT has restricted traffic to a single lane each way near Natrona Heights. Its contractor is fixing the road and bridges as part of a $4.5 million contract.

Delays both coming and going are as time-consuming as they are frustrating. Besides, there's another major construction zone on Route 28 at the Etna interchange, where traffic is likewise funneled into one lane in both directions.

Brad Miller, a PennDOT construction engineer, responded to White's e-mail, thanking him for a "thoughtful letter" and his "patience as we endeavor to provide the motoring public with a smoother, safer and swifter Route 28."

Here's part of Miller's response to White about the Natrona Heights work zone:

"This project includes many enhancements that a regular commuter of Route 28 will appreciate. They include concrete pavement patching; milling and resurfacing of the asphalt shoulders; bridge deck overlays; bridge painting; guide rail; signing; pavement markings; cleaning of fallen rock from the drop zones adjacent to the roadway. In addition, the entire three miles will be diamond-grinded to provide a smooth riding surface.

"As to why we restrict both directions at a time. It is the most time-efficient way to perform the work. Restricting both directions of traffic concurrently, as opposed to sequentially, enables PennDOT to compress the overall time frame. Our schedule reflects this, as our project duration is approximately four months, with the completion date being Nov. 30."

It's not Miller's fault, but PennDOT never explained itself until now. It seldom does.

Correction. PennDOT news releases have announced and spokesman Dick Skrinjar has said on TV and radio that traffic will be maintained one lane each way when Interstate 79 is rebuilt from the ground up between the Crafton-Route 60 and Kirwan Heights interchanges next year and 2006.

"We only publish what we're told and what comes on the information sheets we're given" by engineers, Skrinjar said. "We were given no indication two lanes would be maintained both ways."

Don't panic.

When I checked, engineers assured me that two lanes would be provided in each direction for the duration. That's why PennDOT is spending $3.5 million to repave and build traffic crossovers in the 5.5-mile stretch, which carries more traffic than anywhere else on I-79 between West Virginia and Erie.

Clarification. Television, radio and other newspapers made a big deal Aug. 18-19 about PennDOT's plans to build an $8 million "missing ramp" from Route 28 (East Ohio Street) to Interstate 279, thereby enabling traffic to bypass three obnoxious traffic signals.

A reader wanted to know why he didn't see the story in the Post-Gazette.

That's easy. The PG published the story two months earlier, on June 11, including a map showing where and how the ramp will be threaded over Madison Avenue and under the north end of the Interstate 579/Veterans Memorial Bridge ramps.

PennDOT said it failed to build the ramp as part of the massive North Side interchange construction in the 1980s "for financial reasons."

Bzzzz. Wrong again.

A group called the East North Side Area Council, with support from city government, opposed the ramp, maintaining it would dissuade people from patronizing North Side businesses and professionals and cut off important North Side access.

PennDOT compromised, designing the ramps you see today and eliminating ramps you wish were there.

Update. Dan Beyer berated me last week for dropping Moon Run Bridge 8 (a.k.a. Forest Grove Road overpass of I-79, Kennedy) from listings in "Construction Around the Region."

Beyer said he "heard rumors there are serious problems with the bridge and it may have to be replaced completely. This is important to those of us who live near the bridge."

Dear Dan:

You must have missed what the PG printed Aug. 15, so I'll repeat it.

"The PG tries to list all significant projects when they are announced, but the list is too long for all projects to continue to be published or updated every week, except those with the biggest traffic impacts.

"Also, agencies do not always provide timely notice and complete information about project timetables."

As a courtesy, I've updated the project for this week's construction guide. Usually, people can pick up a phone and find out the same thing.

As for the rumors, the overpass is not in the best of shape. Extra supports have been installed to avoid a weight restriction and extend the life. The county's work over the past six weeks will help considerably.

Park-n-ride relief. More than 500 vehicles fill North Hills park-n-ride lots to capacity, but the Port Authority has had trouble finding more space.

The Perrysville Avenue lot next to the Ross municipal building has been expanded three times, and there is nowhere else to go. The spaces fill early at BladeRunners and at a PennDOT-owned lot, both in Marshall.

"Here's a scoop," Port Authority Engineering-Construction Manager Henry Nutbrown said. "We've found the spot for another park-n-ride lot."

It would be built on property PennDOT owns at the Pittsburgh-Ross line, near the intersection of McKnight Road and Ivory Avenue.

Plans show the lot could accommodate 250 cars.

"People could park and car-pool or take a bus right onto the [I-279] high occupancy vehicle lane," Nutbrown said.

Officials are expected to hold what they call an "informational meeting" about the project within a month.

Believe it! The name Amtrak is a blend of the words "American" and "track." Its official name is National Railroad Passenger Corp.

Plate du jour. Going through the Liberty Tunnels, I spotted the Pennsylvania personalized license plate IM4SNOW on a Dodge 4x4 sport utility vehicle with a ski rack on top. Me? IM4SUN.