The way I'd put it is this: there's enough of it to notice, but not enough that you'll sit in traffic for two hours and miss dinner at home. Aside from I-84 and Route 9 off in Fishkill, there are a lot of one-lane main roads in Beacon, and with the population boom of the area, they do tend to fill up. I remember many times driving through here and being at the back of a long line of cars and going 5-10 MPH under the speed limit; the traffic lights didn't make things much better.
Generally speaking, traffic in the southwestern part of Dutchess County is much worse than it was 10 years ago -- which is to say there really wasn't much. In the last few years, I've seen backups on roads that I'd never seen them on before. Beacon's no exception, so expect some activity on the major roads in town.