An STC value of 32 does not seem very good at all to me. What brand window? I assume this is an insulated glass window and that the laminated portion would be one of the lites, correct? What is the glass makeup? If they are not a really tight well performing window, glass type will not really help that much? What about the insulation of the house? How is the GC sealing everything? Much more needs to be thought of that just the windows.

You should be able to achieve an STC of 32 with dissimilar thicknesses (3/16" over 1/8") of glass without paying the extra for laminated. Laminated would only bump it up to a 33 for five times the cost.
As for whether you accomplish what you want with a 32. Hard to tell without 1) either hiring or bringing into play a sound engineer or some other testing or 2) going into a home that has already been constructed using the glass combination that they are talking to you about. I have done projects with the above 32 and clients have been very happy with it.

32 isn't too shabby at all but that close to the road, more is more.

Ask about whatever glass package they can put together to get it into the 35 ranges.

6.0mm (1/4") laminated glass (1/8" glass / .030" PVB / 1/8" glass) has an STC of 35.

An IG (glass only) with an 1/8" outer lite / 1/4" airspace / 1/4 lami also has an STC of 35, but if you increase the airspace to 1/2" then the STC jumps up to 38.

Unless the sash/frame are very leaky I can't imagine how the window company managed an STC 32 using a laminated lite.

In the same conditions the OITC would be 31...

Thanks for all the replies!

Our builder uses Windsor Windows Next Dimension Classic vinyl. This is the reply that the window guy at the local lumberyard sent me when I asked for the STC:

"Windsor Windows has tested the Next Dimension Classic series with laminated glass at an STC rating of 32."

I'm having trouble finding specific information on the individual glass thicknesses, but the specs say this about the standard windows (not laminated):
"All units include 3/4" double pane LoE 366 insulated glass as standard."

We've been considering dissimilar glass as a cheaper alternative, but I'm told by the rep that the Windsor IG units are made by Cardinal, which does not offer dissimilar glass as an option.

We had JELD-WEN windows in our previous house, and although they seem to get pretty bad reviews online, we didn't have any big problems with them. It seems that JELD-WEN offers dissimilar glass with an STC of 32, so perhaps that's an option. Any thoughts on this? Alternative brands?

Back to the laminated glass...

I'd appreciate any suggestions on economical vinyl windows (one step up from builder's grade) that can achieve an STC of 35 with laminated glass. If we decide to fork out the extra cash for laminated, we want to get the best STC possible for a typical assembly.

Thank you!!

Hold on to your hat because Windsor vinyl just may be worse than Jeldwen,......

That's not good news at all! Is there something specific that makes the Windsor windows bad?

Can I safely assume that there are no "budget" windows that are of decent quality?

Probably a safe bet on that.

Don't blow out the budget but a few extra bucks on windows will pay dividends in the long run.

Broken Arrow - Here is a very helpful and informational article on sound reduction. There are a lot of factors besides the windows
http://www.houselogic.com/home-advice/windows-doors/soundproof-windows/#.

Here is a link that might be useful: House Logic - Soundproof Windows

Personally, i think a 32 - 35 stc would suffice.

32 is not a very high STC rating at all. As others have mentioned, 32 is pretty much standard for most double-pane windows.

I checked Windsor's website and it does not list STC ratings for any of their windows. That's not a good sign.

Thanks, everyone! As I posted in a related thread, it looks like we can go from the builder's window option with an STC of 26-28 to a window with dissimilar glass with an STC of 34. I'm hoping that would be a big enough jump to make it worthwhile. I'm guessing it will be sufficient in the main part of the house, but we may need to consider the addition of a storm window in the bedroom if the traffic noise is still too loud at night. We have a pretty limited budget, so we're looking for the most cost-effective solution.

Fortunately, our home will be all-brick with upgraded insulation, so the walls shouldn't be a major source of noise infiltration.

Going from a 26 to a 34 should provide considerable noise reduction by comparison.

STC comparisons are not linear so the higher the number delta, the greater the impact.