Illicit drugs also are smuggled into and through Texas via commercial aircraft, cars, buses, passenger trains, pedestrians, and package delivery services. Narcotics are also smuggled through the railroads that connect the U.S. and Mexico. Moreover, the Mexican drug traffickers often use small boats to transport drugs through the coastal areas of South Texas, usually operating at night to prevent them from being spotted by law enforcement officials. Another avenue that they have implemented is to construct tunnels to get their product across the border. By constructing a tunnel, the cartel can get their product across the tight border security with the possibility of no detection. Apart from using these common ways, once the product is across the border, common cars and trucks are used for faster distribution in different cities. To use the seas, the cartel also implemented the use of narco submarines.