The Buick Roadmaster is an automobile that was built by Buick from 1936 to 1958, and again from 1991 to 1996. Roadmasters produced between 1936 and 1958 were built on Buick's longest non-limousine wheelbase and shared their basic structure with the entry-level Cadillac Series 65, the Buick Limited, and after 1940, the Oldsmobile 98. Between 1946 and 1957 the Roadmaster served as Buick's flagship.
When it was resurrected for the 1991 through 1996 model years, it became the marque's largest vehicle. The Roadmaster sedan, a C-bodyvehicle over its eight previous generations, shared the B-body for the first time in its history. It was 10 in (254 mm) longer with a 5 in (127 mm) greater wheelbase than the C-body Buick Park Avenue. It was also larger both in wheelbase  (51 mm) and overall length (6 in (152 mm)) than the K-body Cadillac DeVille. The Series 80, which belonged to an upper category trim package and shared with the Series 90, was the first Buick to offer the 344.8 cu in (5,650 cc) OHV Buick Straight-8 engine developing 104 hp (78 kW; 105 PS) at 2800 rpm. It was a new approach for Buick offering a top-level luxury sedan with an eight-cylinder engine which became expected from luxury brands, similar to the Oldsmobile L-Series on the GM C platform. The next year a new high-performance engine was introduced developing 113 hp (84 kW; 115 PS). In 1933, the aesthetics of all Buicks were updated with a new, corporate "streamlined" appearance shared with all GM cars for that year due to GM's Art and Color Studio headed by Harley Earl. 1933 was the first year all GM vehicles were installed with optional vent windows which were initially called “No Draft Individually Controlled Ventilation” later renamed "Ventiplanes" which the patent application was filed on Nov. 28, 1932. It was assigned to the Ternstedt Manufacturing Company, a GM subsidiary that manufactured components for Fisher Body. At the end of 1933, the 80 series was discontinued after 24,117 units produced. In 1936 the model changed its name to "Series 80 Roadmaster". Body style choices were limited to a 2-door coupe or 4-door sedan in 1931 capable of seating either 5- or 7-passengers, then replacing the coupe with a Victoria 5-passenger coupe in 1932. The 1933 model year saw convertibles for both the coupe and 4-door sedan convertible reviving the "phaeton" nameplate again. The origins of the Roadmaster name date to 1936 when Buick added names to its entire model lineup to celebrate the engineering improvements and design advancements over their 1935 models. Buick's Series 40 was named the Special, the Series 50 became the Super, the Series 60 was named the Century and the Series 90 — Buick's largest and most luxurious vehicle — was named the Limited. The Series 50 was retired, but new for the model year was the Series 80 Roadmaster. The 1936 Buick sales brochure describes "It literally named itself the first time a test model leveled out on the open highway.  Styling changes for 1938 were modest, with a longer hood extending to a now nearly vertical grill, taller bumper guards, and redesigned hubcaps. Changes were made to both engine and chassis. The ride was improved by replacing the rear leaf springs with coil springs and incorporating double-acting shock absorbers that were four times the size of others. The frame X-member was changed from I-beam to channel construction and all wood structural elements were replaced with steel. In 1940 the Series 80 was renamed Buick Limited. The Roadmaster name was transferred to the new Series 70, which was introduced at the same time as a brand new Series 50 Super. The Roadmaster featured a cutting-edge "torpedo" C-body. The new C-body that the 1940 Buick Roadmaster shared with the Super, the Cadillac Series 62, the Oldsmobile Series 90, and the Pontiac Torpedo featured shoulder and hip room that was over 5-inch (127 mm) wider, the elimination of running boards and exterior styling that was streamlined and 2-3" lower. When combined with a column-mounted shift lever the cars offered room for six-passengers. The 1942 Roadmaster was longer, lower, wider, and roomier than before (a Harley Earl trademark), due in part to a longer wheelbase. There was also a new vertical-bar grille and "Airfoil" fenders that swept back to the rear fenders, which in subsequent generations became the chromed "Sweepspear". Both features became a Buick icon exhibited in one way or another for years to come, and were influenced by the concept carcalled the Buick Y-Job. The 4-door phaeton was discontinued. Coupes adopted the Sedanet fastback style that was introduced on 1941 on the Century and Special. The new one-piece hood was double-hinged so that either side of the engine compartment could be opened, while in later updates the hood would open at the front and extend up and towards the passenger compartment. In 1947 a new stamped grille with a separate upper bar was used. The Roadmaster name appeared in red-filled script on a chrome button within the bumper guard crossbars, front, and rear. All new was an Estate wagon body style. It sold 300 units and became the top of the line in the station wagon market.In 1948 a series script appeared on the front fenders and the white Tenite steering wheel that had been used previously was replaced with a black version. This also matched the change from a two-tone woodgrain instrument panel to a two-tone gray instrument panel, with silver-finished instruments. A new optional custom trim option was offered, consisting of cloth upholstery with leather bolsters with the robe cord cover and lower door panels trimmed in leatherette. Convertibles acquired power windows, seat, and top as standard equipment. The Dynaflow was introduced, the first passenger car torque converter transmission. Optional on Roadmaster in its first year, it became standard equipment for 1949. Overall sales were just under 80,000 in both 1947 and 1948, over four times greater than in any prewar year.