It is possible to use Speedcam with an IP or Wlan camera. This is sometimes easier to do than with a regular USB camera. You can position the wireless camera closer to the street, and many of these also have a night vision IR lamp that enhances measurement at night.
To use the IP camera with Speedcam, you have to install the free version of ManyCam. This allows you to convert an IP or wireless camera into a native USB camera that works with Speedcam to measure vehicle velocity.