Why is 条 the measure word being used in 那条街名是以一个将军的名字命名的
You are right, the correct classifier for 街名 is 个

那条街是以一个将军的名字命名的. would be the most natural way to speak.


We say 命名街道 (give name to a street), not 命名街名 (give name to a street name)

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If you must use 街名, the correct sentence would be 那个街名是跟據一个将军的名字而起的


We say 起街名 (decide a street name), not 命名街名 (give name to a street name)