In 2001, the Oregon Department of Transportation (ODOT) reduced illumination at select locations on Oregon interstate highways in response to a Governor's directive to conserve power. The illumination reduction occurred for various interchanges and highway sections between October 2001 and March 2002. The research establishes a baseline comparison using the simple before-after method of evaluation to determine if there were any significant changes in overall safety at the locations with reduced illumination and makes recommendations on future modeling efforts. The simple before-after study used ODOT crash data to test five study designs with varying 'before' and 'after' periods. No control sites of volumes were used in this preliminary analysis. The 'before' period ranged from 1 year to 5 years of data and the 'after' period ranged from 1 year to 2 years. It was found that only two study designs produced statistically reliable results. These were the designs with 5 years before and 2 years after and with 3 years before and 2 years after data. Both study designs show that an increase in crashes at the project locations and it was estimated to be between 7 percent and 22 percent with a statistical significance of 95 percent. While these results are an indication that crash frequencies have increased at the project locations during the study period; it cannot conclusively determin

We co-sponsor weekly seminars during the academic year. Seminars are free and open to the public, and may be taken for credit. Please join us: 12:00 to 1:00 p.m. in Room 204 of the Distance Learning Center Wing of the Urban Center on the Portland State University campus Click for a current list of speakers(and archived presentations)