Depends on whether you get a fair an honest judge or a dishonest feudal lord...
The State has to present prima facie evidence of each element of the crime.
The speed limit where the offence took place
That the Officer was trained in the use of the device
The device was used as per manufactures requirements
That the officer tested the unit before the arrest and after the arrest
That your car was the one that the laser (or other instrument) indicated was causing the speed reading
If they fail (which is not all that rare) and you motion for dismissal you should get a non-guilty verdict. Sometimes the officer does not show up - in which case you get quick dismissal.
Additionally, In VA current calibration certificates are required by statute to get the conviction... see statute section below. Lately, the good defense lawyer's in VA have been using this to their advantage and getting aquital (Obviously this is going above the heads of ignorant pretend message board lawyers and arbitrary and capricious LEO's who do not obey the laws (and constituitions) themselves
)
You have this choice (contesting) or the beg for mercy option which will probably only get a reduction or probation...
Either way just showing up everytime will most likely be worth your while.
§ 46.2-882. Determining speed with various devices; certificate as to accuracy of device; arrest without warrant
The speed of any motor vehicle may be determined by the use of (i) a laser speed determination device, (ii) radar, (iii) a microcomputer device that is physically connected to an odometer cable and both measures and records distance traveled and elapsed time to determine the average speed of a motor vehicle, or (iv) a microcomputer device that is located aboard an airplane or helicopter and measures and records distance traveled and elapsed time to determine the average speed of a motor vehicle being operated on highways within the Interstate System of highways as defined in § 33.1-48. The results of such determinations shall be accepted as prima facie evidence of the speed of such motor vehicle in any court or legal proceeding where the speed of the motor vehicle is at issue.
In any court or legal proceeding in which any question arises about the calibration or accuracy of any laser speed determination device, radar, or microcomputer device as described in this section used to determine the speed of any motor vehicle, a certificate, or a true copy thereof, showing the calibration or accuracy of (i) the speedometer of any vehicle, (ii) any tuning fork employed in calibrating or testing the radar or other speed determination device or (iii) any other method employed in calibrating or testing any laser speed determination device, and when and by whom the calibration was made, shall be admissible as evidence of the facts therein stated. No calibration or testing of such device shall be valid for longer than six months.