The only Halachically valid solution for a city that meets the criteria of 600,000 is suggested in a responsa of R’ Chaim Ozer Grodzenski ZT”L. He discusses the possibility of an Eruv in prewar Paris and proposes that if we have three walls of “Omed Merubeh Al HaParutz” (more wall than breach) and one seals off the breaches with a Tzuras HaPesach, there is no need for doors.
The responsa is based on the following: As mentioned, the Mishna Berurah states that we rely on the opinion of the Rambam that “Lo Ossei Rabim U’Mevatlei Mechitzta”. The Rambam states this explicitly in a case of “Shem Daled Mechitzos”. “A construction of four symbolic walls”; an area that is surrounded by four “corner posts” and thereby negating the necessity of doors. If an area is surrounded on three sides with true walls, it is at least equal to the “corner posts” and no doors would be required. This reasoning is explained in the Chazon Ish [107:5] and used by the Bais Ephraim [#26]. (It should be noted that the Bais Ephraim understands that both opinions [even if doors must be closed at night] hold that “Lo Ossei Rabim U’Mevatlei Mechitzta” thereby strengthening the responsa of R’ Chaim Ozer Grodzenski ZT”L.)
The leniency of R’ Chaim Ozer Grodzenski ZT”L is based on the Halacha following Rabbi Elazar that “Lo Asei Rabim etc.” In fact, the Mishne Berurah states that all Eruvin were primarily based on the opinion of Rabbi Elazar. If the Halacha would follow the opinion of Rabbi Yochanan, the only way to construct an Eruv in a big city would be to build a wall with doors that would be closed each night.
This is the basis of the Toronto, West Rogers Park, Chicago and the San Fernando Valley Eruvin.
Notwithstanding the Mishnah Berurah’s (and the Mishkenos Yaakov’s) assertion that the majority of Rishonim pasken asu rabbim u’mevatlei mechitzta, the fact is the overwhelming majority of Rishonim and Achronim maintain lo asu rabbim (see The Overwhelming Majority of Rishonim Maintain Lo Asu Rabbim U’Mevatlei Mechitzta and The Overwhelming Majority of Achronim Maintain Lo Asu Rabbim U’Mevatlei Mechitzta). Therefore, relying on omed merubeh al haparutz is not a leniency at all as this is the accepted halachah. Additionally, Rav Chaim Ozer clearly did not consider a Paris eruv a leniency as can be discerned from the way he accepts the halachic issues without any debate.
As mentioned previously, it is not just the Bais Ephraim and the Chazon Ish who do not differentiate between the two opinions of the Shulchan Aruch. The overwhelming majority of Achronim who maintain lo asu rabbim also do not make such a distinction (see The Shulchan Aruch Explained).
More so, the author is mistaken since all the Rishonim (besides for the Ritva) concur that Rav Yochanan would agree in a situation of mechitzos that are omed merubeh al haparutz we pasken lo asu rabbim (see Like Whom Does the Rif Pasken – like Rav Yehudah or the Chachamim?). Consequentially, if an area is encompassed by mechitzos, all are in agreement that there is no requirement of delasos. Eruvin that utilize mechitzos are clearly superior to those eruvin relying only on tzuras hapesachim, and even a baal nefesh can rely on them (see also Part 2: According to the Mishnah Berurah, May a Baal Nefesh Carry in an Eruv of Tzuras HaPesachim?).
Additionally, there is another valid halachic solution, namely mufulash that the author continuously omits. City streets are not mefulash u’mechuvanim m’shaar l’shaar and therefore are not classified as a reshus harabbim.
Some yeshivaleit persist on declaring that Rav Chaim Ozer Grodzenski zt”l’s heter to establish an eruv for Paris was a great leniency. This falsity comes from a misplaced antipathy towards city eruvin believing that being machmer in eruvin is a lofty goal. Therefore, they cannot accept that a posek of the stature of Rav Chaim Ozer would allow an eruv in a large city. In truth, if they would learn hilchos eruvin, they would realize that Rav Chaim Ozer was only relying on accepted halachah for Paris and not some novel approach to constructing an eruv (see Part 1: The Achiezer Explained).
The LA Eruv Guidebook:
In Halachic terms, the newly constructed Eruv is a substantial upgrade. Firstly, there are many intricate Halachos regarding the actual construction and placement of the Tzuras HaPesach. Our Eruv follows the more stringent opinion, while the former Eruv relied on various leniencies. Secondly, since most Poskim regard Los Angeles as meeting the criteria of “600,000”, a Tzuras HaPesach Eruv does not suffice, and an Eruv is only valid if constructed in a manner of “Omed Merubeh etc.” with the breaches closed by Tzuras HaPesach.
Most poskim would not agree that LA would be classified as a reshus harabbim even without mechitzos since there is no street that has either shishim ribo traversing it or a street that is mefulash. (Although it is wonderful that currently we are able to establish an eruv mehudar, it is important to note that our grandparents used eruvin that had nowhere near the level of enhancements we can integrate in the construction of eruvin today.)
The LA Eruv Guidebook:
Rav Moshe Feinstein zt”l was undoubtedly the recognized Posek of the United States. As such, it would be inappropriate, perhaps even forbidden, to construct an Eruv which he deemed to be invalid. This Eruv, however, does meet the Halachic requirements of Rav Moshe Feinstein zt”l, as attested to in writing by his son, Horav Dovid Feinstein Shlit”a.
The following is a synopsis of the Shita of Rav Moshe Feinstein zt”l: While Rav Moshe Feinstein zt”l followed the lenient interpretation that a street is only considered a Reshus HaRabim if 600,000 people traverse it daily, nevertheless he introduced a second manner in which a heavily populated city can become a Reshus HaRabim. According to Rav Moshe Feinstein zt”l, even if there is no single street that is traveled daily by 600,000 people, nevertheless, if an 80 square mile area of a city is populated by enough people that one can assume that there are 600,000 people out on the street during daytime hours, this entire area would be considered a Reshus HaRabim, even though no single street has a traffic of 600,000 people.
Accordingly, Rav Moshe Feinstein zt”l posits that if a city has a population density in this “square” of 2 ½ to 3 million people, we can assume that there are 600,000 people on the streets at any given time. Rav Moshe Feinstein zt”l [אג"מ או"ח ח"ה סי' כ"ח ענף ב' אות ה'] proves that merely having a population of 600,000 is not sufficient from the fact that Warsaw had an Eruv even though there were more than 600,000 residents. Since the relevant “square” in Los Angeles has a population of just approximately 700,000 people, even if we would combine commuter traffic, it would surely be permitted according to the guidelines of his responsa.
Rav Moshe Feinstein zt”l, in another responsa, restricts construction of an Eruv in a city that is densely populated and people would assume that there are 2 ½ to 3 million people in the “square” even though actually there are not that many people. Since Los Angeles is a very “spread out” city, one can reasonably assume that Rav Moshe Feinstein zt”l would not restrict construction of an Eruv in Los Angeles. His son, Horav Dovid Feinstein Shlit”a, in fact, has written to us that his father zt”l would permit construction of an Eruv in Los Angeles.
This is one of the most accurate synopses of Rav Moshe Feinstein zt”l’s shita regarding shishim ribo to date and the author deserves credit for it. However, there are a few issues that should be illuminated. First of all, it is wrong to suggest that if Rav Moshe would prohibit an eruv it would be forbidden to establish one. Every single rav has a right and a responsibility to establish an eruv if he maintains that one can be erected (see Eruvin: Who’s Obligation). Why should eruvin be any different then any other halachic issue? More so, Rav Moshe himself allowed the rabbanim of Manhattan to establish an eruv even though he was of the opinion that one cannot be erected (see Hagaon Rav Moshe Feinstein zt”l’s Reluctance to Pasken Against the Establishment of an Eruv).
Additionally, it is the Shulchan Aruch’s ruling that a street is only classified as a reshus harabbim if shishim ribo traverse it daily and that is whom Rav Moshe is following, not just any lenient opinion (see Shishim Ribo According to the Achronim: A Daily Requirement or Not). Furthermore, in Rav Moshe’s last teshuvos regarding the amount of people required to populate an area of twelve mil by twelve mil he clearly settles on the figure of 3,000,000 people. Only then would have Rav Moshe classified the area as a reshus harabbim (see Part 2: Shishim Ribo According to Hagaon Rav Moshe Feinstein zt”l).
Regarding Rav Moshe zt”l’s gezeirah – that people would assume that the twelve mil by twelve mil area contains 3,000,000 people – he mentions this even regarding Detriot proper (see Three Million: More or Less?). Detroit’s population at the time Rav Moshe wrote his teshuvah (1980) was approximately 1.2 million and nevertheless Rav Moshe maintained that Detroit is one of the cities that people would assume contained a population of 3,000,000. Therefore, Rav Moshe upheld that an eruv cannot be erected there. Thus, according to Rav Moshe, it is presumptuous to claim that LA is a city that one would not imagine contained a large enough population to be classified as a reshus harabbim. The question is why Rav Dovid Feinstein shlita did not declare that because of his father’s gezeirah an eruv cannot be established in Chicago and Los Angeles. It seems that this gezeirah was not considered by Rav Dovid a serious enough issue to impede the construction of eruvin, after all (see Three Million: More or Less?).