I have a cheaper driveway monitor, it works 95% of the time but the sensor is buried beside the drive, would probably be better under the drive. Sometimes the UPS truck makes it in without setting it off and sets it off on the way out.
Mighty Mule Wireless Driveway Alarm (FM231) https://www.amazon.com/gp/product/B003765W0W/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I have been thinking of buying the Dakota, hoping it would be 100% reliable, but would still like to burry beside the drive if possible. Would be hard digging to the center of the drive.
I live on a 1200' drive with a corner and lots of trees so the house is barely visible even in the Winter so I get very few unexpected cars. The alarm I have is setup by the corner about 300' from the house. I use to have it about 200' from the entrance but it was really unreliable with the trees and hills.