Question: When did the manufacturer of VTEC, the owner of Scion, and Nissan open US assembly plants?

Knowledge 1: Scion (automobile)
Scion is a discontinued marque of Toyota that started in 2003. It was designed as an extension of its efforts to appeal towards younger customers. The Scion brand primarily featured sports compact vehicles (primarily badge engineered from Toyota's international models), a simplified "pure price" model, and eschewed trim levels in favor of offering a single trim for each vehicle with a range of factory and aftermarket options for buyers to choose from to personalize their vehicle. The "Scion" name, meaning the descendant of a family or heir, refers both to the brand's cars and their owners. The brand first soft launched in the United States at selected Toyota dealers in the state of California in June 2003, before expanding nationwide by February 2004. In 2010, Scion expanded into Canada. In an effort to target the generation Y demographic, Scion primarily relied on guerrilla and viral marketing techniques. [SEP] Knowledge 2: Toyota
By the early 1960s, the US had begun placing stiff import tariffs on certain vehicles. The so - called ``chicken tax ''of 1964 placed a 25% tax on imported light trucks. In response to the tariff, Toyota, Nissan Motor Co. and Honda Motor Co. began building plants in the US by the early 1980s. [SEP] Knowledge 3: Variable Cylinder Management
Variable Cylinder Management (VCM) is Honda's term for its variable displacement technology, which saves fuel by using the i-VTEC system to disable one bank of cylinders during specific driving conditions—for example, highway driving. The 2008–12 Accords took this a step further, allowing the engine to go from 6 cylinders, down to 4, and further down to 3 as the computer sees fit.
Knowledge 1: 1973 oil crisis
Some buyers lamented the small size of the first Japanese compacts, and both Toyota and Nissan (then known as Datsun) introduced larger cars such as the Toyota Corona Mark II, the Toyota Cressida, the Mazda 616 and Datsun 810, which added passenger space and amenities such as air conditioning, power steering, AM-FM radios, and even power windows and central locking without increasing the price of the vehicle. A decade after the 1973 oil crisis, Honda, Toyota and Nissan, affected by the 1981 voluntary export restraints, opened US assembly plants and established their luxury divisions (Acura, Lexus and Infiniti, respectively) to distinguish themselves from their mass-market brands. [SEP] Knowledge 2: Scion xD
The Scion xD is a five-door subcompact hatchback marketed in the U.S. and Canada by Japanese manufacturer Toyota beginning with the 2008 model year — replacing the xA. The Scion xD and the second generation xB were first shown to the public on February 8, 2007 at the Chicago Auto Show. The xD appeared in Scion showrooms in mid-2007 in the USA and in 2011 for Canada. The Scion xD was discontinued in 2014, and was succeeded by the Toyota C-HR in 2017. [SEP] Knowledge 3: Variable Cylinder Management
Variable Cylinder Management (VCM) is Honda's term for its variable displacement technology, which saves fuel by using the i-VTEC system to disable one bank of cylinders during specific driving conditions—for example, highway driving. The 2008–12 Accords took this a step further, allowing the engine to go from 6 cylinders, down to 4, and further down to 3 as the computer sees fit.
Knowledge 1: 1973 oil crisis
Some buyers lamented the small size of the first Japanese compacts, and both Toyota and Nissan (then known as Datsun) introduced larger cars such as the Toyota Corona Mark II, the Toyota Cressida, the Mazda 616 and Datsun 810, which added passenger space and amenities such as air conditioning, power steering, AM-FM radios, and even power windows and central locking without increasing the price of the vehicle. A decade after the 1973 oil crisis, Honda, Toyota and Nissan, affected by the 1981 voluntary export restraints, opened US assembly plants and established their luxury divisions (Acura, Lexus and Infiniti, respectively) to distinguish themselves from their mass-market brands. [SEP] Knowledge 2: Scion bbX
The Scion bbX was first concept car to be revealed by Toyota for its daughter company, Scion. The concept was first shown at the New York International Auto Show in 2003. As shown at the motor show, the bbX is very similar to the design of the Scion xB, sold for two generations from 2003 to 2015. [SEP] Knowledge 3: Variable Cylinder Management
Variable Cylinder Management (VCM) is Honda's term for its variable displacement technology, which saves fuel by using the i-VTEC system to disable one bank of cylinders during specific driving conditions—for example, highway driving. The 2008–12 Accords took this a step further, allowing the engine to go from 6 cylinders, down to 4, and further down to 3 as the computer sees fit.

Answer: 1981