There are traffic sounds ascending the hill on which I live. Might a "white noise" generator inside my small studio apartment have impact on this type of noise, or is noise impact on individuals simply too subjective for an answer?
A white noise generator is like spraying perfume to cover a nasty smell. The smell is still there, just the perfume is stronger. The nastier the smell, the stronger the perfume needs to be to cover.
A white noise generator produces noise that our brain quickly ignores. If this noise is louder that the outside noise, then it will mask it. But a word of warning, if you have to turn the white noise generator up enough to cover loud outside sounds you might risk your hearing. Even though our brain doesn't 'hear' the white noise, our ears still do. And a constant loud noise will produce hearing loss over time.
Brownian aka Brown noise, with its lower frequency emphasis, might do the trick. It works for me but I don't get any serious traffic noise (mostly 100+ yards away). I use an old MP3 player and created a 4-hour track that repeats. GoldWave and Audacity can generate Brown noise easily. Another option is white noise with bass boosted. Traffic noise tends to have lower registers, so regular white noise is too "hissy" to mask enough of it. Pink noise is sort of a cross between White and Brown - try that also.