Subpoena the Speed Device Measuring Expert in Washington State

[macroplaza]

I received a ticket in Kennewick, Washington (Benton County) on 08-12-06 for going 52 mph in a 35 mph zone. I will not be able to get my ticket deferred since I already received one in March of 2005 in Cowlitz County.

A lawyer here in Seattle says that one approach could be to subpoena the officer and the Speed Device Measuring Expert. He says that the officer may or may not show up, but that there might be an even lesser chance that the Speed Device Measuring Expert will show up and thus could help me win the case.

Does anyone know about this approach and what the probability is that I can win using this approach?

I have been scheduled to appear on Oct. 3 at the Prosser Court House for Benton County.

Thank you very much.