Location dialogue keeps fighting traffic noise, lav or boom?

Both, always both. Lavs for safety, boom for character. And record 60 seconds of clean room tone before you wrap the location, you'll thank yourself in the mix.

Shoot the wide with the traffic and grab the close-ups at 6am. Cheaper than a restoration plugin.

Modern dialogue isolation tools are scary good now, but they still can't fix a clipped lav. Gain-stage conservatively and you're fine.