Roslyn Farms, Pennsylvania Speed Traps

I was getting onto I279 going towards Pittsburgh when I was pulled over. I was told that I had been going 40 mph in a 25 mph zone. I was on a two-lane road in a quiet, upscale neighborhood and didn’t see any speed limit signs posted. I do not know where the officer was located but I was only on the road for less than half a mile. It seemed like the most obvious trap because I was getting onto a busy interstate and had to speed up but was pulled over while I was in the process.