You can probably create a second column "tempDate" and then run a query like:
UPDATE vehicle_inspections SET tempDate =VehiclesDate
If it doesn't copy that way, then as long as you have a standard date format you might be able to get it to work with str_to_date() like:
UPDATE vehicle_inspections SET tempDate = str_to_date(VehiclesDate, '%Y-%m-%d')
Then once you are sure the dates got copied to the new column properly, delete the old column and rename the new one.