Guagua is the word for "Bus" used in Cuba, Puerto Rico, and Dominican Republic. Apparently, the first company to built buses to export to these island was established in Washington, DC and all of them carried the following letters (WAWA) that stand for the company name that I cannot remember now.
The prize goes to juanjacob51.
La palabra “guagua” que para los cubanos significa autob?s
Viene del Ingl?s Wa & Wa Co. Inc. (Washington, Walton,
And Company Incorporated) que fue la primera f?brica
estadounidense en exportar autobuses a la isla. El logo de
Wa & Wa Co Inc era una liebre blanca, azul y roja, colores
de la bandera norteamericana, (y de la cubana tambi?n) y
figuraba prominentemente en el frente, fondo y costados
de todos sus autobuses.
?Sobre el origen de la palabra "guagua"? - Yahoo! Respuestas
This makes sense. It's like calling all breakfast cereals confle, after corn flakes.