Our criminal lawyers at Caldicott Lawyers are experts in all traffic matters and specifically in the area of speeding.

It is an offence to exceed the designated speed limit. 

Usually a sign will be erected and visible to drivers. This sign will have a number representing the number of kilometres per hour applicable to the length of road. If the person exceeds that speed then they are guilty of an offence.

If a speed limit sign does not apply to a particular length of road then a default speed limit is implemented. The default speed limit applying to a road in a built-up area is 50 kilometres per hour. The default speed limit for any other road is 100 kilometres per hour.

This offence is contained in Rule 20 of the Australian Road Rules.

Our criminal lawyers at Caldicott Lawyers are experts in all traffic matters and specifically in the area of speeding.

The maximum penalty for speeding is a fine of $2,500.

If you do decide to plead guilty to a speeding offence or any other driving offence we can assist you to get the best result possible.

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

We can, in certain circumstances, achieve less demerit points being incurred for speeding offences which may avoid any potential licence disqualification.

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. Regardless, 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) were used or where the prescribed conditions for using that speed detection device were not complied with.

In some cases the speed of a vehicle may be determined by the police following and timing an offender whilst in his vehicle. This method is commonly referred to as ‘Time and Follow’. There is criteria that makes this method of detection valid. Often police will not be able to adequately calculate the speed using this method resulting 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 that there was some other technical defect which will offer a defence to this charge.

Honest and reasonable mistake of fact (Proudman vs 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 of speeding 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 overlapp 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 have been held to include disorders such as:

  • Schizophrenia
  • Hyperglycaemia
  • Psychomotor epilepsy
  • Cerebral arteriosclerosis

The Prosecution must prove:

  1. what the speed limit was on the road
  2. that you were driving a motor vehicle, and
  3. that your vehicle was travelling at a speed above the speed limit.

To prove a speeding offence police usually rely on devices such as lasers, radars and speed cameras. Police observation can also be used to indicate the offence of speeding.

In most circumstances, an expiation notice is sent out to the registered owner of the motor vehicle. If you elect to be prosecuted or if you are also charged with other offences the matter will be heard in the Magistrates Court of South Australia.

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