Image from National Institute of Standards & Technology.

Particularly now that  Melendez-Diaz v. Massachusetts, 129 S.Ct. 2527 (2009), has become firmly entrenched in the Constitutional landscape, Sixth Amendment challenges to machine-based speed calculations should be more persuasive than ever when the people who calibrated the machine do not testify live at trial.

Virginia, for instance, has the following statutory provision for the admissibility of testimony on such machines as lasers and radars:

"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." Va. Code § 46.2-882.

Certificates of such calibration or accuracy sound like testimonial evidence that is not admissible without live testimony from the people who certified the calibration and accuracy. Melendez-Diaz v. Massachusetts, 129 S.Ct. 2527.