A study conducted for a conference of U.S. mayors suggests that the housing crisis is not over, but that measures can be taken to reduce its impact on the economy. Mayors from across the nation are meeting in Detroit today to discuss policy recommendations they plan to propose at a conference in January.

The report, titled “The Mortgage Crisis: Economic and Fiscal Implications for Metro Areas,” conducted by Global Insight, says that less residential investment, lower spending and income in the construction industry and weak consumer spending because of lower home values will slow economic activity next year. New York is expected to lose $10.4 billion in economic activity in 2008, Los Angeles could lose $8.3 billion, Dallas and Washington could be down $4 billion and Chicago could drop by $3.9 billion.

The report also estimates that the U.S. gross domestic product will grow 1.9 percent next year, but that the GDP would have been $166 billion, or one percentage point, higher if not for the mortgage problems. It expects property values to decline by $1.2 trillion, with home prices dropping an average of 7 percent.

Yet, the study also says that homeowners, banks, holders of mortgage-backed securities and loan servicers can work together to contain the effects of the mortgage crisis, such as agreeing to new payment terms on some loans.