Defences to drink driving
For the most part, in the modern era it is very hard to establish a defence to a drink driving charge. There are, however, a number of potential defences available, which do succeed from time to time if they are valid and there is appropriate proof. This article takes a look at them.
(1) Driver consumed alcohol after driving but before police administered test
Essentially, the defence is that since the driver consumed alcohol between the time that he stopped driving and the time that the police administered a breath test, the alcohol level shown in the breath test is greater than it was when the driver was driving.
A difficulty with this defence, of course, is that the driver needs to show (probably using expert scientific evidence) that the alcohol he consumed after driving accounts for the fact that his breath alcohol was above the limit at the time of testing.
The prosecution might seek to counter this defence if there is evidence from an additional test administered some time after the first one. Using the rate at which the body metabolises alcohol, the prosecution might use such evidence to argue that the driver's breath alcohol would have been above the legal limit when he was driving.
(2) Police failed to adhere to required procedures
The police should follow a set procedure and give a driver certain warnings if they administer a blood or urine test instead of a breath test. For example, the police are required to give the driver the statutory reason that they cannot use a breath test, and they must warn the driver that he can be prosecuted if he fails to provide the requested blood or urine test.
In fact, if a prosecutor determines that the police failed to follow mandatory procedures in obtaining a sample, he might abandon the case for want of evidence (assuming there is no other evidence to support prosecution).
(3) Driver had reasonable excuse for failing to provide a test sample
Ordinarily a driver will need to produce medical evidence to raise this defence. If he does so, the prosecution will have the burden of proving that there was no reasonable excuse, and might do so by raising questions about the validity of the driver's medical evidence and/or introducing medical evidence of its own.
Where a driver raises this defence, the court will consider whether the medical evidence shows that the driver had the claimed physical or mental condition and whether that condition caused him to be unable to give the requested sample.
(4) Driver was given a drink that was spiked or laced with alcohol
To use this defence successfully, a driver will need to show that (i) the spiked or laced drink was what put him over the legal alcohol limit, (ii) he had not known that the drink was spiked, and (iii) he was not aware of being over the alcohol limit.
In raising this defence, the driver is claiming that emergency circumstances forced him to drive whilst under the influence of alcohol. Depending on the nature of the emergency and the distance driven, a court may be willing to take it into account, but in general this is rarely an effective defence.
(6) Threat or duress
Drivers have sometimes advanced the defence that they were forced to drive whilst over the limit either because they were fleeing an imminent threat or they were coerced into driving. In evaluating this defence, a court would likely consider the nature and immediacy of the threat or coercion, the distance driven (and whether it was more than was strictly necessary to escape from the threat), and whether the driver's intoxication caused him to perceive a threat that was more imagined than real.
(7) Driver did not drive on the public highway
This defence could work if the driver did not drive on a public highway or other public place. For this purpose, however, a parking lot, petrol station forecourt or similar facility is regarded as a public place. The reason for this is that even though such places may be private property, members of the public generally have access to them and are likely to be present.
(8) Unreliable test results
Proving test results are unreliable is very hard in the modern age. Most defendants who succeed either convince the court that the breath test machine calibrations were outside acceptable boundaries or demonstrate the presence of high acetone levels in the breath specimen.
As technology improves and devices become more reliable, the scope to challenge results on either basis has narrowed. The devices now used in police stations have become far more adept at differentiating between the various substances contained in a specimen.
Thus, you should think very carefully and consult your solicitor at length before you decide to challenge your test results. Certainly rethink any defence strategy advanced purely as a "shot in the dark" to reduce the penalty the court imposes, since this approach is usually doomed to failure and invariably just leads to an increased sentence.
Getting help with a drink driving charge
If you've been charged with a drink driving related offence, you are strongly advised to seek legal advice as a matter of priority. You can find a criminal law solicitor in your area for free via Contact Law.
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