Device drivers for Windows 7 can be designed so that standard users can install them without being prompted to supply administrator credentials for the computer. Unfortunately, not all device drivers behave this way. Specifically, if the device driver launches a co-installer (for example, a Setup program) that the user is required to interact with during installation, then elevation will be required.
If users in your environment are standard users and they are encountering such a situation when they try and install a device on their computers, you should contact the device vendor and ask them if they have a driver package that doesn't prompt for elevation.
Mitch Tulloch is a seven-time recipient of the Microsoft Most Valuable Professional (MVP) award and widely recognized expert on Windows administration, deployment and virtualization. For more tips by Mitch you can follow him on Twitter or friend him on Facebook.