In the past, an event attracting 1.5 million to CenterCity would cause congestion, traffic, and delays that we in urban life expect occasionally. Since 9/11, however, such crowds call for stronger security concerns. So strong that the city and its residents, visitors, institutions, and businesses must halt all normal activity before, during, and after.

For this week's papal visit, local officials and the Secret Service will seal off some areas of the city and many transportation options for most of four days. Non-papal activities — events, trips, construction — will be virtually impossible. We will be relegated to the 14th century, with the best transportation option being our feet and what we can carry. And Lord help whoever needs a plumber that weekend.

There has been a steady, confusing stream of changing information about the closures, but there is no single source for them. It's doubtful that people have fully absorbed the scope of the disruption of city life.

Think about it: The city's maps on their phila.gov/informationcenters/pope website show that, developing in stages that began Sunday evening, private and commercial vehicles are restricted in central Philadelphia.  Specifically, at that early time, from the Reading Terminal at 12th Street to beyond the Art Museum at 26th Street, for six blocks wide, all street-parked vehicles must be removed. Tuesday at 6pm., that area is extended to Independence Hall.

Beginning Thursday at 10 p.m., a "Secure Perimeter" enclosing City Hall and the Art Museum, three blocks wide, will prevent even pedestrian traffic, creating a wall across the city.  Friday at 6 p.m., a "Traffic Box" to exclude incoming vehicles, from the Delaware to the Schuylkill, and from South Street to Girard Avenue, takes effect. At 10 p.m., it reaches its full extent, to 38th Street in West Philadelphia, and another fenced area is erected around Independence Mall.  The final Traffic Box encompasses an area three miles east to west and two miles north to south, equivalent to a large swath of midtown Manhattan.

Beginning Friday at 10 p.m., the state is closing the Schuylkill Expressway from Conshohocken to the WaltWhitmanBridge, the Vine Street Expressway, and a section of City Avenue, as described by PennDOT's website. It doesn't say when they will reopen.

All of SEPTA's major resources for the weekend — commuter rail, subways, and suburban trolleys — will be devoted to delivering passengers to and from the few open stations for the papal events. Transit trips to most other destinations will be difficult. Passengers will not even be able to connect between the Broad Street and Market-Frankford subways, as City Hall Station will be closed, as will Suburban Station. SEPTA's website lists many canceled bus routes , while north-south bus routes will not run between Cecil B. Moore and Washington Avenue on Friday, Saturday, and Sunday. Quite a walk.

When Mayor Nutter proclaims that Philadelphia will be open for business, what Philadelphia is he referring to? In addition to transportation closures, according to the phila.gov/pope fact sheet, courts will be closed most of the week and city offices will be operating on a "reduced services basis" Thursday  through Monday. Schools will be closing, too.

How can all this happen without the consent of the governed? The city says the Traffic Box is necessary for the safety of the huge pedestrian crowds, even though the box extends far from the events themselves and is maintained throughout the night. Why some specific street closures for designated pedestrian routes wouldn't be sufficient is a mystery. In fact, the official "2015 Philadelphia Papal Visit Guide" designates just such routes, even though they are inside the Traffic Box.

The other secure zones and closed SEPTA stations are, thanks to the Secret Service, to facilitate vehicle control and personal screening. How did it get involved? The papal visit has been designated a National Special Security Event (NSSE) — a potential terrorism target — by the Department of Homeland Security, which authorizes Secret Service  involvement. The authorizing legislation allows the Secret Service to "participate ... in the planning, coordination, and implementation of security operations" for NSSEs, but not control them. Local authorities are not supposed to be subservient to the Secret Service, although rejecting their recommendations may come at a high price.

Whether these security measures can prevent an attack, either inside the restricted areas or immediately outside, will be seen. However, what is clear is that the long disruption of the citizenry for this or any other private large event is untenable. The estimated economic value, even if it is achieved, is not worth the costs and limits placed on ordinary citizens going about their lives and livelihood.

When the papal postmortems are done, let us declare that we will host no more large events that impose this kind of tyranny. Of course we still have an NSSE coming up next year, the Democratic National Convention. The New York Times reported in February that former Governor Rendell has already suggested  that Broad Street be closed from the Convention Center to the WellsFargoCenter to ease delegate transportation. Yes, the rest of us will just have to get out of the way.

Our leaders need to know that Philadelphia is a working city, not an amusement park that can be closed at their whim. They must fully recognize the crowd and security consequences of such events and not solicit them. Or, if they must, plan to host them on Belmont Plateau in FairmountPark, at the NortheastAirport, or, better yet, the mayor's house.

John Lehman is a naval architect with a practice in Center City, where he and his family reside. jtl@lehman-navarch.com