routes.rb

rake routes

search_reservation_departure GET    /reservation/departure(.:format)                                    departures#search {:destination=>/\w+/}
       reservation_departure GET    /reservation/departure(.:format)                                    departures#show
  search_reservation_arrival GET    /reservation/arrival(.:format)                                      arrivals#search {:source=>/\w+/}
         reservation_arrival GET    /reservation/arrival(.:format)                                      arrivals#show
             new_reservation GET    /reservation/new(.:format)                                          reservations#new

routes.rb

  resource :reservation, :only => [:new] do
    resource :departure, :only => [:show] do # 検索の選択画面はここのshow
      collection do
        get :search, :destination => /\w+/, :path => '' # 検索結果はこっち。
      end
    end
    resource :arrival, :only => [:show] do
      collection do
        get :search, :source => /\w+/, :path => ''
      end
    end
  end