It is an offence to drive at a speed exceeding the speed limit by 45 km/hour or more. 

This offence is contained in section 45A of the Road Traffic Act 1961 (SA). 

Our criminal lawyers at Caldicott Lawyers are experts in all driving matters and specifically exceeding the speed limit by 45 km/hour or more. 

For a first offence of exceeding the speed limit by 45 km/hour, the maximum penalty is a fine of $1,000 and you will be disqualified from holding a driver’s licence for at least six months.

For a subsequent offence the maximum penalty is a fine of $1,200 and you will be disqualified from holding a driver’s licence for at least two years.

Deciding whether or not to plead guilty has important implications and should be made after proper discussions with a criminal lawyer.

If you do decide to plead guilty we can assist you to get the best result possible.

Our team of specialist criminal lawyers have extensive criminal law experience and know the best way to present your case before each of the Magistrates in the State. The results they obtain speak for themselves.

Call 08 8120 3783 to make an appointment with one of the knowledgeable lawyers at Caldicott Lawyers for assistance with your driving matter.

You weren’t driving

In some cases the wrong person is charged with an offence. There are a variety of ways in which this can occur. It may be that there was an administrative error on the prosecution’s behalf or perhaps, the offender was carrying your identification which they presented to police. It is a complete defence to this charge if it can be shown that you were not driving the vehicle.

No Proof of Your Speed

You will have a defence to this charge in the event that no prescribed means of speed detection (e.g. speed camera) was used.

In some cases the speed of a vehicle may be determined by the police following and timing an offender whilst in their vehicle. This method is commonly referred to as ‘Time and Follow’. There is criteria that makes this method of detection valid. However, often police will not be able to adequately calculate the speed using this method which may result in the charges being withdrawn.

Defective equipment used to measure speed

In some cases your most appropriate defence might be of a slightly more technical nature and may require the evidence of experts in the relevant field to defend the charge. In relation to speeding offences it may be possible to present evidence to show that the speed detection device had been miscalibrated, that there was interference from another vehicle, or any number of other technical defects which will offer a defence to this charge.

Reasonable and honest mistake of fact (Proudman v Dayman Defence)

If you genuinely believed that the speed at which you were travelling was less than or equal to the prescribed limit and it was reasonable for you to hold that belief (e.g. defective speedometer) then you may have a defence to this charge.


It is a complete defence to this charge if we can show that you were acting under duress. That is, you were acting as a result of violence, or some other threat against you. The Court will need to be presented with evidence that indicates that you were coerced into the act by a third party, effectively rendering you an instrument of someone else’s criminal conduct.


The common law defence of necessity operates where the circumstances at hand (natural or human threats) require you to break the law in order to avoid even more dire consequences. Thus, there is some overlap with the defence of duress. It will need to be shown that you believed on reasonable grounds that you were placed in a situation of imminent peril. You may have a medical justification or it may be the case that you were acting in the course of protecting yourself or someone else.

Essentially, the Court will need to weigh up the act you have committed against the harm you would have experienced had you not acted in that manner. Further, the Court will need to be convinced that the act was proportionate to the potential harm.

Mental impairment

The law recognises that in some cases people will not be capable of evaluating the nature and quality of their conduct or more categorically, they will not know what they are doing is wrong. If it can be shown that you were suffering from some sort of mental disease, disorder or disturbance, as distinguished from a mere lack of self-control or impulsiveness, then you may have a defence to this charge.

Mental impairments may be either permanent or non-permanent and may include disorders such as:

  • Schizophrenia
  • Hyperglycaemia
  • Psychomotor epilepsy
  • Cerebral arteriosclerosis

Trifling Application or Application for Reduction of Demerit Points

Trifling application or any other proper cause: made immediately after conviction may have the effect of reducing the amount of demerit points. The same magistrate is required as the one who convicted the defendant to hear the evidence and decide if the offence is trifling or whether any other proper cause for reduction exists Zanker v Hyndman.

Proper cause must relate to the offence itself. The fact that may suffer hardship from recording demerit points not amount to proper cause Hepworth v Rowbottom.

The Prosecution must prove:

  1. the speed limit;
  2. that you were driving a motor vehicle; and,
  3. that your vehicle was travelling at a speed of 45 km/hour above the speed limit.

This matter will be dealt with in the Magistrates Court of South Australia.

Come and see the helpful team at Caldicott Lawyers for assistance in your matter.