A. No. According to the vast majority of poskim, an eruv can be erected in Brooklyn since it's not considered a reshus harabim d'Oraysa.
Most poskim maintain that Brooklyn is not classified as a reshus harabbim because of the following three reasons:
- The streets of our community do not run straight from one end of the city to the other ― they are not mefulash u’mechuvanim m’shaar l’shaar.
- None of the streets in our community, including Ocean Parkway, are traversed daily by 600,000 people ― there is no shishim ribo ovrim bo b’chol yom.
- As Brooklyn is circumscribed by more than three mechitzos at its waterfront, it is fundamentally a reshus hayachid.
Even one of the above conditions would be sufficient ground to permit an eruv of tzuras hapesachim. Additionally, as there are many reasons to allow an eruv in Brooklyn, even a Baal Nefesh can utilize the eruv with certainty. Furthermore, since Brooklyn is bounded on three sides by mechitzos, any eruv in Brooklyn would be considered a Rambam eruv.
Q. Doesn’t Ocean Parkway have more than shishim ribo passing through it every day?
A. No. The statistical records of the Department of Transportation [DOT] show that Ocean Parkway, one of Brooklyn’s main thoroughfares, has fewer then 55,000 vehicles traversing it daily in both directions  [with an average of 1.5 occupants per vehicle ]. Therefore, even Ocean Parkway, the largest thoroughfare included in the parameters of the eruv, would not pose a problem for the establishment of an eruv of tzuras hapesachim. Some claim that since Ocean Parkway merges with other roadways, the collective traffic should be factored into the total count. Consequently, since almost all roads are connected at some point, they would then all be considered as one roadway. Following this illogical line of reasoning further, it would be impossible to erect eruvin in any city because all roadways would have, collectively, shishim ribo traversing them.
More so, this issue is a moot point according to most poskim since Ocean Parkway doesn’t continue straight [mefulash u’mechuvanim] into these other roadways and they are therefore not halachically considered as one. Furthermore, Hagaon Harav Moshe Feinstein zt”l maintained that in order for any section of an intercity road to be considered a reshus harabbim, shishim ribo would have to traverse that particular section of the road on a daily basis. Accordingly, we would not include vehicles entering the roadway at different points in the total count, as they are each traveling along different segments of the roadway. Since Ocean Parkway has much fewer than shishim ribo traversing it at any point, there is no question that Rav Moshe would not classify it as a reshus harabbim. Additionally, the poskim maintain that people traversing the road in both directions are only counted traveling in one direction and so the total for a roadway like Ocean Parkway is actually much less. Hence, we can conclude that Brooklyn does not have a street that has shishim ribo traversing it.
[Even more so, most poskim maintain that cars are not tallied in the shishim ribo. The reason is either because a vehicle in itself is considered a reshus hayachid and therefore its occupants are not part of the total or because we only include pedestrians (holchei regel) who traverse the street in the tally. Consequently, it is clear that there is no street in Brooklyn that has shishim ribo traversing it.] Moreover, since Brooklyn is encircled with mechitzos, notwithstanding how many people traverse Ocean Parkway, it’s nonetheless classified as a reshus hayachid.
Q. Didn't Hagaon Harav Moshe Feinstein zt"l categorically forbid the establishment of an eruv in Brooklyn?
A. Rav Moshe permitted an eruv to be erected in Kew Gardens Hills, Queens and in Detroit. In regards to Brooklyn, Rav Moshe acknowledged to the rabbanim of Flatbush that as there were many opinions on the topic of reshus harabim, he did not want to join them in the matter; however, he did not forbid them to construct an eruv. [Concerning Rav Moshe’s signature on the kol korei of 1979 and 1981 which prohibit the Boro Park and Flatbush eruvin, see The 1981 Boro Park Kol Korei Exposed and The 1979 Flatbush Kol Korei Exposed for evidence that both are spurious documents and cannot be relied on.]
Moreover, Rav Moshe's reservations regarding erecting an eruv in Boro Park and Flatbush was based on misinformation provided to him at the time, such as: Brooklyn’s population was more than 3,000,000  [the population required according to Rav Moshe to classify the area as a reshus harabim of shishim ribo] while in fact, according to census figures, Brooklyn only has 2,465,326 residents.
Rav Moshe was incorrectly informed, as well, that Boro Park and Flatbush each have a population of more than shishim ribo  [if the eruv included a population of less than shishim ribo an eruv could be established just as Rav Moshe allowed an eruv in Kew Gardens Hills, Queens] when, in fact, the Boro Park eruv encompasses a population of under 100,000 residents, and in Flatbush, the eruv includes a population of less than 200,000 people. Additionally, Rav Moshe wrote that he was not certain if Brooklyn had mechitzos  [if in fact Brooklyn did have mechitzos, it would not be considered a reshus harabim d'Oraysa ]. It has now been established that Brooklyn is bounded by man-made mechitzos on three sides, hence an eruv can be erected in Brooklyn even according to Rav Moshe’s shita.
It is important to note, Hagaon Harav Tuvia Goldstein zt”l Rosh Yeshiva of Emek Halacha and a Talmid/Chaver of Hagaon Harav Moshe Feinstein zt”l, said on numerous occasions that even after the 1979 kol korei against the Flatbush eruv was printed, he spoke with Rav Moshe who agreed that if the rabbanim wanted to erect an eruv they could do as they saw fit. [Moreover, he stated that even Rav Moshe himself would have allowed an eruv in its present construction.]
 Divrei Malkiel, 4:3; Achiezer, 4:8; Minchas Elazar, 3:4; Chazon Ish, O.C. 74:10, 107:4-7; Rav Shlomo Dovid Kahane zt”l, one of the main rabbanim of Warsaw before World War II, Divrei Menachem, O.C. vol. 2, pages 42-43; Bais Av, 2:5:2; Rav Yisroel Yaakov Fisher zt”l in Even Yisroel, 8:36, and Kinyan Torah, 4:40.
 See The Community Eruv, note 11.
 See The Community Eruv, note 5.
 See The Community Eruv, pages 67-8.
 NYSDOT, A Transportation Profile of NYS, 2004 page 4.
 Igros Moshe, O.C. 5:28:16.
 Kuntres Tikkun Eruvin Manhattan, page 108; Kinyan Torah, 4:40:7, and Rechovas Ha’ir, 23:2.
 Bais Ephraim, O.C. 26; Maharsham, 1:162; Yeshuos Malko, siman 26-27; Harei B’samim, 5:73; Bais Av, 2:9:3; Mahari Stief, siman 68; Satmar Rav zt”l, as cited in Kuntres Meoz U’Mekedem, page 27; Divrei Yatziv, 2:172:13; V’yaan Yoseph, 1:155:1; Kuntres Tikkun Eruvin Manhattan, siman 12 page 105; Kinyan Torah, 4:40:6, and Rabbi Eliezer Y. Waldenberg shlita, author of the Tzitz Eliezer, as cited in The Contemporary Eruv, 2002 page 54 note 119.
 Igros Moshe, O.C. 4:86 and 5:29.
 Ibid., 4:87; see also Hagaon Rav Moshe Feinstein zt”l’s Reluctance to Pasken Against the Establishment of an Eruv.
 Ibid., 5:28:5, 5:29; see also Part 2: Shishim Ribo According to Hagaon Rav Moshe Feinstein zt”l.
 Census 2000 Summary File 1.
 Igros Moshe, O.C. 5:28:5 and Addendum to O.C. 4:89; see also Does the Eruv Encompass Shishim Ribo?.
 NYC Department of City Planning, Community District Profiles, 2006; see also The Community Eruv, section two.
 Igros Moshe, O.C. 5:28:5.
 Ibid., 1:139:3.
 See The Community Eruv, section two and four.
 See Questions and Answers Regarding the Flatbush Eruv, Hebrew section, page 7.