[SECProto]

You have to have 4 years of accredited experience working under an already-certified professional engineer. This experience get audited, and references get called to confirm the types of experience and whether it is adequate. The auditor is free to say "this two month period and that six month period were not adequate experience. You have to get 8 more months experience before you can qualify." It's not the exam alone, but rather the combination of multiple factors: required education, required experience, examinations, and ongoing professional training (required to do several dozen hours per year of certified professional training to stay current).