<P> Rationing access, rather than gasoline, based on number plate parity can reduce traffic congestion . In some areas, wealthier people purposely own two cars with opposite - parity number plates, to circumvent any restrictions . Vanity plates which do not contain any digits may be arbitrarily classed as odd or even . </P> <P> Zero is an even number; indeed, half of the numbers in a given range end in 0, 2, 4, 6, 8 and the other half in 1, 3, 5, 7, 9, so it makes sense to include 0 with the other even digits for rationing . However, many people are unaware that zero is even, and this ignorance can cause confusion . The relevant legislation sometimes stipulates that zero is even . In fact, an odd--even restriction on driving in 1977 Paris did lead to confusion when the rules were unclear . On an odd - only day, the police avoided fining drivers whose plates ended in 0, because they did not know whether 0 was even . </P> <P> Odd--even rationing was instituted in the U.S. as part of the response to the second gasoline crisis in 1979, when turbulent conditions in Iraq and Iran led to worldwide oil price increases, even though a supply shortage did not materialize in the U.S. </P> <P> After Hurricane Sandy hit the eastern coast in late October 2012, gasoline became scarce and caused lines to extend miles past stations and people to wait for hours to fill cars or gasoline tanks for generators powering houses without electricity . Panic buying and fuel hoarding began to occur within days of the storm . On November 3, 2012, New Jersey governor Chris Christie issued a gas rationing system to follow the odd--even rule to ease lines in 12 counties . A few days later on November 8, New York City Mayor Michael Bloomberg, along with Nassau County Executive Ed Mangano and Suffolk County Executive Steve Bellone, instituted an odd--even rationing system due to gasoline shortages from Hurricane Sandy . In New York City, such rationing lasted through November 23 due to the increased travel and gasoline demand during the Thanksgiving week, while it ended more than a week earlier in the other counties . License plates without numbers, such as vanity plates, were considered odd . </P>

When were the gas lines in the 70's