What is a lay witness not allowed to give evidence about in relation to drink drive offences?

Answer 1

A lay witness is any witness who does not testify as an expert witness under oath in a court of law. The opinion of a lay witness at court is generally inadmissible. They can give evidence of facts which have been observed by their physical senses (e.g. sight, hearing, smell, touch or taste.)

A lay witness is not allowed to provide knowledge not normally possessed by the average person concerning the drink driving offence. Only an 'expert' witness can do this. An expert in a particular field can be called upon to state an opinion on a matter which is within his specialist knowledge and which is something upon which a layman could not be expected to form an opinion because of the skills required.

For example, in drink driving cases, a lay witness is not allowed to give evidence in the following areas:

• the weight, height, build, age and sex of the driver;
• details of any food consumed from six hours before the offence and the provision of a breath or laboratory specimen;
• any known medical condition;
• details of any medication taken regularly, or within 4 hours prior to drinking;
• the type and quantity of alcohol consumed before the offence and, if possible, the times at which individual units of alcohol were consumed;
• the same information concerning any alcohol allegedly consumed after the offence but before the provision of a breath or laboratory specimen.
• evidence of mathematical calculations based upon the elimination of alcohol within the driver's body over a period of time.