Smart phones and dash cams may produce video evidence to defend yourself with in traffic court. However, it's not a good plan to show up with your smartphone in hand and try to show that video to both the prosection and the judical justice while you explain your point. In fact, some judicial justices will refuse to allow you to enter evidence in this manner.
Properly, the evidence that you tender needs to be turned over to the court and held for 30 days until the appeal period for the case ends. Would you want to hand over your smart phone for 30 days or even longer than that if you choose to appeal the outcome?
The court registry that I contacted for advice suggested that you bring your video to court on either a DVD or USB flash drive and that you save the file in a format compatible with the Windows operating system.
Equipment availability varies from courtroom to courtroom. To insure that your video evidence is shown to your best advantage, you should contact the court registry at the location your trial will be held well ahead of time to prepare. They will be able to advise what is available to you and the best format to tender it in.
Providing your evidence in advance may get the case dismissed before you even go to Court.
If you lose your case appeal to a higher Court as Traffic Court normally just rubber stand a GUILTY on the paper work before you even begin. If you can appeal your chances of winning are very high.