Traffic lights, as well as antennas, can be very tricky. Those two obstacles have the same method of elimination, but have one small difference:

  

Traffic lights - you need to match 3 or more cars next to the light to turn it ON. DO NOT match cars next to an ON light again, or you will turn the light OFF. When all lights are ON, they will disappear.

Antennas - similarly to lights, you also need to turn all the antennas ON in order to get rid of them. The difference is that once the antennas are ON, they don't turn OFF, luckily. Once you turn all the antennas ON, they will disappear.