How long does it take to find and fix a flat? (Including time to find and remove whatever caused the puncture in the first place.)
Your desire to accelerate faster is noted. But before the crit racers pile on with their "rotating weight" concerns, how much faster do you really think you can accelerate, given a normal commuting load (whatever that is for you), normal clothing (including rain gear?), and, I assume, the fact you're not an accomplished racer with a body mass index under 20.
Treat your normal commuting as a chance for interval training, and I expect you'll find you can deal with the traffic AND get to work on time just fine with the heavier tire.