No expert, but I really notice the difference when I close our double pane glass casement windows and French doors. They have three-point locks that pull them close against the insulation. Window open, I can hear cars on our road. Windows closed, I can't hear a car driving up to our house on the gravel driveway.

We live in a concrete house with triple pane windows and the outside noises are really reduced when compared to other houses we have lived in.

Foam insulation over exterior sheathing under the siding will reduce noise and increase the home's energy conservation.

Laminated Glass in windows and doors, or at the very least offset thickness in the double pane IGU. Minimal expansion spray foam around the windows and doors after proper installation will also help.

Minimize the area dedicated to windows on the high traffic side - as blank a wall as possible on street side. Use double or triple-glazed ones.

Use skylights and light wells.

Research noise minimizing construction techniques, such as the "staggered studs" to prevent low frequencies from passing through the wall.

We have closed cell insulation and our house is incredibly quiet.

Sound in a building is transmitted in three ways:

1. Airborne transmission - a noise source in outside or in one room sends air pressure waves which induce vibration to one side of a wall or element of structure. One sound control method is adding mass into the structure, such as a heavy dividing wall, which will usually reduce airborne sound transmission better than a light one. Another common solution in light framed construction is mounting wall and ceiling boards on resilient clips, decoupled from framing members. Air tightness also becomes an important control technique. Sealing all penetrations on walls where airborne transmissions occur is important.
2. Impact transmission - a noise source outside or in one room results from an impact of an object onto a separating surface, such as heat pump, air conditioner, furnace, fan unit, washer or dryer, etc. Acoustic control measures usually include attempts to isolate the source of the impact, or cushioning it. Duct isolators often help reduce sound transmitted via ducting.
3. Flanking transmission - a more complex form of noise transmission, where the resultant vibrations from a noise source are transmitted to other rooms of the building usually by elements of structure within the building. This is more common in steel and concrete framed buildings than in wood-framed ones.

Thus, one needs a combined noise reduction strategy if the sound is a significant factor. Good luck on your project.

We live on a highway and the best thing we ever did was to get 6 mm laminated replacement windows. We barely hear anything now, unless it's a siren going by.

I lived in MSP a few blocks from the airport. Two months before I purchased the home, built in 1932, the airport came in and put in custom built triple-pane Marvin windows, new doors and blew in an extra foot of attic insulation. Couldn't here a 747 if it flew directly overhead. I still miss those windows.