Martin Riggs' trailer is a mobile home that remains inoperable and maintained on the beach in Los Angeles, California. It is where Martin Riggs lives with his dog Sam (and later a Rottweiler). Other than a beachfront addition, the trailer has remained unchanged throughout the series.
The trailer is shown one cloudy morning in a beach in California, miles away from Los Angeles. Sam runs towards the trailer to greet his owner Martin Riggs, who awakes from his bed naked while he prepares for work.
Riggs later returns to his trailer, more depressed than usual and loads his gun with a hollow point bullet. It is here that he contemplates suicide before changing his mind.
Lethal Weapon 2
Riggs is seen at his trailer again in the second film; he and his dog Sam are sitting out on the beach, and then they both go inside to watch The Three Stooges.
Riggs goes back to his trailer to see Sam out of it and that Leo is cleaning up his trailer. He then helps Murtaugh out at his house with the problem being a bomb on his toilet.
After handling the situation, Roger watches over Leo, and Martin meets up with Rika Van Den Haas and invites her over to his place for dinner. As the evening falls upon, the two have their moment of intimacy; meanwhile, some of the officers investigating the kruggerrand case are being killed one-by-one by Pieter Vorstedt under the orders of Arjen Rudd.
Rudd and Vorstedt sent out a helicopter to Riggs' place. Riggs and Rika wake up to be ambushed by Rudd and Vorstedt's henchmen. Riggs kills them one-by-one and shoots down the helicopter; and he, Rika, and Sam all get away unharmed, but Riggs' trailer is completely totaled in the process from the ambush.
Lethal Weapon 3
The trailer appears briefly in the third film; following the events of the second film, Riggs supposedly hired Mickey McGee to renovate and attach his trailer next to a new home sometime after he finished expanding Murtaugh's house.
Riggs brings home Lorna Cole and his newly befriended Rottweiler and he, the Rottweiler, and Sam, watch The Three Stooges on TV and share some laughs.
Later, Riggs has a talk with McGee about the final costs of the renovation when Rianne shows up and McGee says he will come by next week.
Lethal Weapon 4
Martin Riggs' trailer is now attached next to the house Mickey McGee built specifically for him. Lorna has since moved in with him and are now expecting their first born child together.