Original URL: http://www.theregister.co.uk/2010/04/02/speeding_ticket_source_code/

Software engineer demands source of his speeding collar

Code slip?

By Gavin Clarke

Posted in Software, 2nd April 2010 14:02 GMT

Updated A US software engineer hopes to beat a speeding ticket by challenging the accuracy of the computerized radar gun used to snare him.

Michael Felch has been granted a request by a Florida court hearing his case for the source code on the LTI 20/20 radar gun that was used in his collar to be turned over for his examination.

Felch, due in court on April 8, told The Reg that he wants to examine the code in order to find out whether changes have been made to fix a problem in the code (reported here and here) that has been claimed to miscalculate a car's speed.

The reported "slip" effect happens when the laser beam used to calculate speed moves along the car while taking its reading, giving a higher, false reading. The device's maker has in the past denied problems with false readings.

Felch was cited for driving at 64mph in a 40mph zone. The engineer, though, claimed that speed would have been impossible as he was taking a right-hand corner from a standing stop on a red light. Felch has one prior speeding conviction.

Felch was stopped for speeding on January 7 and the court granted Felch his request on February 22. On March 29 he filed a motion to compel the State of Florida to provide the code, which has not yet been delivered.

The radar gun itself is supplied in the US by Laser Technology, who was unavailable for comment at the time of writing.

"I don't believe they handled the slip effect correctly," Felch said of the device. "I believe there can be a miscalculation that can lead to plus or minus 30 miles per hour."

It's unclear what will happen should the source code not be delivered in time for Felch's hearing. An employee of the Polk County Court handling the case contacted by The Reg said Thursday: "We don't discuss what's going to happen in court because we don't know."

Felch said what happens next will be down to the discretion of the court. If the code is delivered he will file for a continuance in order to examine the bits and bytes. If there's no code, then the case could be dismissed or the judge could simply go to a ruling.

History is not on his side. In November 2005, another Florida court, in Sarasota County, hearing a drunk-driving case, ordered that the code for the breathalyzer used in that collar to be handed over for examination by the defendant.

Despite the court order, all research suggests that the code was not handed over by the breathalyzer's manufacturer. The defendant, meanwhile, was convicted anyway and the case closed a year later in November 2006.

You can read more on Felch's blog here. ®

This article has been updated to clarify the motion to compel was filed against the State of Florida, not Laser Technology.