Executive summary: EyeCheck is a non-invasive instrument which introduces a light stimulus to a subject's pupil and measures the subsequent pupillary reaction or pupillary dynamic. Pupillary movement provides indications of activity within the body's central nervous system. Interpretation of pupillary reaction has assisted in determining possible impairment caused by alcohol, drugs, or fatigue. ... On July 1, 2000, Public Act 91-881 was passed and amended 625 ILCS 5/11-501.5 adding paragraph (b) to the section. The added paragraph states, "The Department of State Police shall create a pilot program to establish the effectiveness of pupillometer technology." The bill mandated an 18-month pilot program utilizing 15 instruments. The purpose of the project was to determine if pupillometer technology could detect motor drivers' impairment caused by alcohol and/or drugs. In addition, the amendment specified the measurement of fatigue levels in commercial motor vehicle-drivers. ... The pilot involved collecting data for 18-months and on November 15, 2002, data was forwarded to the New England College of Optometry for analysis. Upon analysis, it was concluded pupillometry can be used as an objective measure to screen and identify reduced alertness as a result of sleepiness or fatigue. It was also determined Pupillometry can be used to screen and identify subjects potentially under the influence of drugs.