TM shows SH 46 with a south end at I-84 exit 157. Since 2010, this has not been the case, and 46 now continues south to end at US 30 just southeast of Buhl.
If this was left out in the past due to being unsigned, that is no longer the case. Signage is not amazing by any means, but there are straight arrows heading south at the I-84 interchange...
...and if you keep going south, after that first bend to the west, there is in fact a reassurance marker: