It should come as no surprise that trucking freight can be a more cost-effective method of transporting cargo, as compared to air and sea-based methods. This is why tractor trailers often make international trips across North America to transport goods from origin to destination. One of the most important factors which allows trucking to be so cost-effective is the minimization of costs; after all, typically only a single driver is required for the actual transport of the goods, as opposed to a ship or aircraft crew. In addition, shipping by road often requires no more than one loading and offloading sequence, whereas shipping by air or sea usually necessitates two such sequences for the initial and final legs of the trip – which are typically road-based – in addition to the loading and unloading of the aircraft or ship. Of course, there are limitations to trucking freight exclusively, the most obvious of which is the inability to transport goods over geographical barriers like mountain ranges and seas. However, trucking freight does allow delivery services to certain remote locations that are inland, which would not otherwise be accessible due to lack of waterway access or no airstrip at the destination.