Vast majority of people don't drive just because a road got wider either. Build a 2x3 highway pointing nowhere and you'll get just a dozen of enthusiasts hold an illegal race on an empty road...
That's the real reason you build more and wider roads. But it's for some reason sold as a way to reduce traffic.
Even if it happens your way... Is it wrong that an interesting location opens up at the end of new road? E.g. a restaurant or trailhead? Yes, it would increase traffic. But on the other hand, this would also let people do things.