The Halacha states (OC 110) that Tefilas HaDerech is only said after a traveler leaves his city to embark on a journey of at least one Parsah. It can be said the entire journey until he arrives within a Parsa of his destination. What happens if alongside the highway that he travels, there is always a city within one Parsa? Is he exempt from Tefilas HaDerech because within a Parsa of a city there is no danger?
The Biur Halacha is Misupak and does not resolve this question. However Rav Vosner (Shevet HaLevi 10:21) says that one should say Tefilas HaDerech in this case. He explains that before leaving your city you are exempt because your journey has not yet begun. Within a Parsa of your destination it is already too late because you've already arrived. The entire road in between, is the modern day danger that is the subject of our Tefilah. The fact that the road is within the boundaries of another city does not lessen the danger as your car whizzes right by it, and therefore does not exempt you.
Important Note: We bring this tshuvah as a starting point for discussion and not to convey any halacha. We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. One should learn the tshuva to verify the accuracy of our interpretation. Please understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.