Regardless of individual opinions on this subject, I personally think the safest mode of transportation will be either water transport or air transport. But if i was forced to choose, i'll simply go with water transport.
Water transport is by far the safest mode of transportation because cases of accident are rarely recorded as opposed to air and road transport. Air transport also has a low record of accident compared to road transportation. But I must admit, in accident situations involving water and air transport, the fatality is usually high, and in almost all cases, the entire passengers as well as crew are lost. And as you know, air and water transport carry more passengers at one time than road transport. So, the fatality record in a single air or water transport accident will amount to tens of road accident fatality. This is the major flaw on the supposed safe mode of transportation.