תנו רבנן דרך היחיד ארבע אמות דרך מעיר לעיר שמונה אמות. דרך הרבים שש עשרה אמות דרך ערי מקלט שלשים ושתים אמות
Our Rabbis taught: A private path is of the width of four cubits; a path from one town to another is to have a width of eight cubits; a public road, 16 cubits; the road to the cities of refuge, 32 cubits.
Rambam (Moses Maimonides), Mishneh Torah
The court is obligated to straighten the roads to the cities of refuge, to repair them and broaden them. They must remove all impediments and obstacles… bridges should be built (over all natural barriers) so as not to delay one who is fleeing to [the city of refuge]. The width of a road to a city of refuge should not be less than 32 cubits. “Refuge, Refuge” was written at all crossroads so that the perpetrator of manslaughter should recognize the way and turn there.