The area discussed
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Several years ago, it was publicized that a section of Highway 444 between the Gamzu interchange and the bridge of Highway 6 was built over a burial cave. After an intensive examination, it came out that the cave was only under the left lane of the highway.
At the time, the Modi'in Illit beis din headed by HaRav Shlomo Zalman Ulman zt"l and HaRav Meir Kessler and HaRav Y. Cohen, sat in discussion about whether to allow usage of the right lane for traffic. The question was brought before HaRav Eliashiv who ruled that it was permissible to use the right lane but not the left one.
The rabbonim of the beis din issued a directive to kohanim traveling on this highway from south to north, that is, from the Gamzu interchange towards Elad and Rosh HaAyin to travel only in the right lane. Admittedly, such a directive requires drivers to pay special heed, but kohanim who are not vigilant will transgress the prohibition of profaning priestly sanctity.
The even greater challenge in such situations is when the forbidden section is part of a public transportation route or a central highway of public bus transportation. Indeed, the said section serves those from Kiryat Sefer traveling to Bnei Brak on a daily basis, as well as public transportation to Elad.
Under normal circumstances, this should not be problematic because the right lane is usually the accepted route for buses, but actual travel reveals that it was quite likely that during heavy traffic, drivers veer over to the "forbidden" left lane. Probability shows that every bus load is likely to include several kohanim, not all of him are aware of the problem, and not all buses precisely travel the kosher lane.
The rabbonim of Modi'in Illit, headed by the city's chief rabbi, exerted themselves in the matter of said road and reached an agreement with the Transportation Ministry that all buses are mandated to use the right lane exclusively, and this is even included in the franchise contract signed by the different companies servicing those cities and signed by their drivers.
In addition, the office of the chief rabbi of Kiryat Sefer publicizes once a year a warning to kohanim to pay attention that this agreement is carried out, and to remind the drivers in advance. It seems from recent reports and testimonies that it is being honored. Most of the drivers are not even Jewish and are irked by such passenger requests of the kohanim.
Now, before bein hazmanim, activists at the headquarters of "Guide to Kohanim" provide information and advice to kohanim which is crucial in planning outings. It is highly advised to consult them before planning an excursion so as to avoid obstacles and pitfalls. Tel. 08-3132020.