There are many types of driveway sensors but most are typically a specialist form of PIR sensor designed to detect heat and movement in a very narrow field of view. These are sometimes called 'curtain' sensors. In this respect they operate much like a beam break sensor.
The attributes of a driveway sensor are that they are weather-proof and designed for external use. Many come with covers to protect them from the sun, rain and snow. Typically that can detect over quite a long range (e.g. >10m) and are good at avoiding false triggering from things moving in the wind.
Commercial products come is various forms, some are wireless and some use batteries. Many have adjustable sensitivity, to enable vehicles, people and animals to be detected. Most commercial products come with a 'base station' to enable visual and audible warnings when triggered. Many support multiple sensors and zones.
PIR sensors often struggle to detect vehicles in cold weather conditions because the vehicles often match the outside temperature. You also need to be careful to install them such that birds won't land on them.
