NYC-WTC_000187725

NYC 9/11 Public Portal Document

42

This aggregation resulted in 454 zones for residence and employment, and in 52 larger zones covering the same area for commerce or shopping. In addition, NYREG has three housing types. Hence; o employment zones I = residential zones J = 454, o shopping zones L = 52, o single family units k = 1, o condominiums and cooperatives k = 2, and o rental apartments k = 3. In Manhattan, single family units are less than one percent of stock. Hence, condominiums and cooperatives and single family units were aggregated in Manhattan. Nearly all zones outside of Manhattan contained each of the three housing types. In the five suburban zones, condominiums and cooperatives were aggregated with apartments as multifamily housing. The peripheral super zone was treated as a zone (with a fixed utility level) for which an equilibrium rent is not determined. Households employed within the study area can choose to reside in this zone. Hence, the study area is open with some households working within the four boroughs and the five suburban zones and choosing the peripheral super zone.®

Travel mode choices reported for commuters in the 1980 Census were aggregated into five modes, as shown in Table 2.2. The zone to zone travel times of the commuting population were calculated as the averages of the reported times from the 1980 Census. These times were assumed to hold in both peak and off-peak periods. For shopping travel, all modes other than auto are aggregated into one mode, called "other".

The housing stock of each zone was decremented by the stock which is occupied by households working in the peripheral zone. Single family and multifamily housing remaining after this decrementing was assumed to be in the same proportion as the stock of the entire suburban county. The vacancy rate for the included stock was assumed to be the same as the vacancy rate of the county as a whole. 6 The definition of the peripheral super zone is not entirely satisfactory. It includes areas of Connecticut, New Jersey, and Nassau County, Long Island, which are too close to the centrally located four boroughs to be classified as peripheral. Further model development will address this problem.

CITY_21MC100_006662273

NYC-WTC_000187773