The answer is it depends on what kind of ticket it is; photo radar vs. in-person ticket. If it is a photo radar ticket, there is a statute that lists the various requirements the government must meet before a ticket can be issued based on the radar. That statute is ORS 810.439. If it was an in-person ticket, meaning issued by the officer themselves, there are times when you can make a good argument based on the evidence, but that is a very fact-specific argument, not to be discussed in this forum.
If you want to fight your ticket, hiring an attorney is not a bad idea, as the attorney can make those arguments for you, possibly using case law of their own in support. Good luck.
In my humble opinion your best strategy involves one of two choices:
A. Hire a good lawyer who is familiar with the evidentiary laws of your state and is also familiar with the jurisdiction in which your case is pending or;
B. Obey the speed limit. (This option is both cheaper and safer too)
Mr. Thygerson provided a sound response to your question. Instead of focusing your efforts on trying to beat a speeding ticket, please consciously be more aware of practicing safe driving skills to avoid future tickets. Good luck to you.
No attorney/client relationship is formed between the attorney responding to this question and the individual asking the question.