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 The Census Bureau determined that it could adopt some of these suggestions. As a result, the Census Bureau expanded the criteria for acceptable census block boundaries, allowing more frequent use of street extensions and other nonstandard features as a method to break up large census blocks. In addition, the Census Bureau adopted the use of an alphabetic suffix attached to the originally assigned census block number to facilitate the reporting of block-level data by governmental unit.

The Census Bureau also approved the recommendation to allow States to identify specific features they wanted the Census Bureau to hold as block boundaries. States that had contracted for block statistics in the 1980 census often found it difficult to use the resulting census blocks to delineate election precinct boundaries because these boundaries frequently did not coincide with the census block boundaries. As a result, States that had paid the Census Bureau to receive block-level data incurred additional expenses to receive detailed data for census blocks split by precinct boundaries. In addition, these States were forced to modify the Census Bureau’s population counts and develop population estimates conforming to the redistribution of population within the adjusted boundaries.

In five States in 1984, the Census Bureau tested the feasibility of implementing the recommendation that States be allowed to specify individual block boundaries that would correspond to voting district boundaries. Two important assumptions for this test were that (1) the Census Bureau would hold all named roads and railroad boundaries as census block boundaries, and (2) the Census Bureau would hold all double-line drainage, as shown on the United States Geological Survey (USGS) quadrangle maps, as census block boundaries.

Technical staff from the States visited the Census Bureau’s regional offices (ROs) to review the maps that RO staff were updating for entry into the Topologically Integrated Geographic Encoding and Referencing (TIGER) data base and for subsequent use to prepare the 1990 census enumeration maps. They compared these feature change maps (FCMs) to their own Voting Districts14-11