This paper presents an analysis of data from the Highway Safety Information System (HSIS) for the State of Illinois. Our analyses focuses on whether various changes in road network infrastructure can be associated with changes in road fatalities and reported accidents. We also evaluate models that control for demographic changes. County-level time-series data is used and fixed effect negative binomial models are estimated. Results cannot confirm the hypothesis that changes in road infrastructure have been beneficial for safety. Increases in the number of lane and increased lane widths appear to increase traffic-related fatalities. Increases in outside shoulder width appear to be associated with a decrease in accidents but an increase in fatalities. Including demographic results does not significantly change results but does capture much of the residual time trend in the models. No statistical association with changes in safety is found for median widths, inside shoulder widths, and horizontal and vertical curvature.