Our Gemara on Amud Aleph tells us about the various ways the sages expressed their love for the Land of Israel:

רַבִּי אַבָּא מְנַשֵּׁק כֵּיפֵי דְעַכּוֹ. רַבִּי חֲנִינָא מְתַקֵּן מַתְקָלַיָּה

Rabbi Abba would kiss the rocks of Akko, which was on the coast of Eretz Yisrael. Rabbi Ḥanina would repair its stumbling blocks, i.e., any potholes in the land, so that travelers would not fall and consequently speak ill of Eretz Yisrael

One might ask, why is this such a chiddush that Rabbi Chanina would remove stumbling blocks in Israel?  Aren’t we all obligated to remove stumbling blocks?  

A personal touch is always better when it comes to relationships.  The same act or gesture when done personally has more meaning than doing it indirectly.  This may be why the Gemara (Kiddushin 41a) says that a mitzvah is best performed yourself than by an agent:

גְּמָ' הַשְׁתָּא בִּשְׁלוּחוֹ מְקַדֵּשׁ בּוֹ מִיבַּעְיָא אָמַר רַב יוֹסֵף מִצְוָה בּוֹ יוֹתֵר מִבִּשְׁלוּחוֹ כִּי הָא דְּרַב סָפְרָא מְחָרֵיךְ רֵישָׁא רָבָא מָלַח שִׁיבּוּטָא

The Gemara starts by questioning the need for the seemingly extraneous halakha stated in the mishna: Now that the mishna stated that one can betroth a woman by means of his agent, is it necessary to state that a man can betroth a woman by himself? Rav Yosef says: The mishna writes both halakhos to teach that although the betrothal is valid either way, it is more fitting that the mitzva be performed by the man himself than by means of his agent. This is like that story of Rav Safra, who would himself singe the head of an animal on Shabbos eve to prepare it to be eaten on Shabbos, and Rava, who would salt a fish himself, to fulfill the mitzva to prepare for Shabbos, although this could have been done by others.

Keeping this in mind, we can answer that in most areas there is a municipality that takes care of the roads and streets, so it is not necessary to do this task. Rabbi Chanina went out of his way to do it personally to show love for Eretz Yisrael. But then the question returns because, assuming it is a mitzvah to take care of stumbling blocks, why would it not be better to do it personally even outside of Israel? (By the way, it is not necessarily Lifnei Iver Lo Siten Michshol to leave actual stumbling blocks, as the peshuto shel mikra is a metaphor for bad advice or causing to sin, and putting a real stumbling block may not be lifnei Iver, see Minchas Chinuch 232.)

I think the answer may be that it is not universally true that it is better to do the mitzvah personally over an agent. Perhaps it is only applicable when doing it yourself adds a qualitative or subjective difference.  That is, in the example of an agent for marriage or honoring Shabbos, by doing it personally, one is showing affection and honor.  So too, with maintaining the roads and streets of Eretz Yisrael.  However, to maintain secular roads, though important, it is just as well if done by the municipality.