A report issued by the Insurance Institute for Highway Safety says increased speed limits on Interstate highways led to nearly 1,900 extra deaths in 22 states from 1996 to 1999. The report, released on November 24, says people are adjusting to drive above the new limits. "What happens is if you raise the speed limits, people go faster," said Susan Ferguson, a top researcher at the Insurance Institute, a safety group financed by car insurers. "It's not that more people follow the law." In 1995, the federal government repealed its speed limits — 55 miles an hour, or 65 on rural Interstates — and sent authority back to the states. Twenty-eight states have raised rural Interstate speed limits to at least 70 miles an hour. The Insurance Institute's report has several components. It highlights a recent study by the Land Transport Safety Authority of New Zealand, which appears to have done a more thorough study of the increased speed limits in the United States than the Transportation Department, which was essentially taken out of the business of setting speed limits by Congress. The New Zealand study focuses on 22 states that raised their limits to 70 or 75 m.p.h. almost immediately after the repeal of the federal cap. Trends from those states are compared with trends in 12 states that kept their limits at 65. The study found 1,880 more deaths on the Interstates in those 22 states from 1996 to 1999, though the authors noted that geographical effects might have skewed the results because most of the states that went to 75 were in the West. The finding appears to show that drivers in states with higher speed limits drive faster. In Maryland, where the Interstate speed limit is 65 m.p.h., the mean speed was 66. About 1 percent of drivers exceeded 80 m.p.h. By contrast, in Colorado, where the interstate speed limit is 75, the mean speed was 76. About a quarter of drivers regularly went over 80.