There's some group on YouTube that do search and recovery of drowned vehicles. Usually on long missing persons.

They basically recreate the situation known on the day the people disappeared and then track down the most likely place a car would have gone off the road. Iirc one video where they ended up finding the missing car in a pond on a farm. Seems the driveway was right in line with the road, driver didn't notice the change in pavement and drove straight into the pond. Farm owner had no idea the car was there.

Interesting and sad .