What year was a Rial Arc2 chassis used?
CREATE TABLE table_name_55 (year INTEGER, chassis VARCHAR)
SELECT SUM(year) FROM table_name_55 WHERE chassis = "rial arc2"
### Context: CREATE TABLE table_name_55 (year INTEGER, chassis VARCHAR) ### Question: What year was a Rial Arc2 chassis used? ### Answer: SELECT SUM(year) FROM table_name_55 WHERE chassis = "rial arc2"