Seems like my first acquaintances with the word "rodent" were heavily associated with animals being identified as "rodents" either when they were seen crossing a road, or when they were seen as road kill. So I thought they were called rodents because they were animals likely to be seen in the road.
A childhood belief about general

others believed things like this
- i always thought that a DEAD END sign
as where they put all the road kill.
— pav - I used to think that if you went to the end of a road marked "Dead End", somebody would try to kill you.— Spooky
- When I was little, I used to believe that deer could only cross the road at the deer crossing signs. — Shellie
- I thought when a road sight said Dead End that someone had actually died there.Anon
- I thought you were supposed to drive down the center of the road.— Cassiopeia
- I used to see "End Road Work" signs, and thought they were a sort of protest.— Sebastian