Fewer people failed breath tests in Essex last month than in November last year.
But officers found that more drivers refused or were not able to do the tests after they were pulled over by officers.
And seven motorists were arrested on suspicion of driving under the influence of drugs.
Road policing inspector Mark Harman said: "Although the number of people arrested may have dropped, there has been a significant increase in those who are refusing or simply unable to provide a specimen of breath."
Essex Police figures for the first half of its drink-drive campaign showed that 4.3 per cent of drivers who were stopped gave a positive breath sampled.
In November 2002, the figure was slightly higher, 4.7 per cent.
During the month, officers tested 2,644 tests, with 113 people providing positive breath specimens and another 22 refusing or failing to give a sample.
Published Thursday December 18, 2003
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