Impact of freeway geometric and incident characteristics on incident detection

The potential improvement in incident detection can be achieved by examining the major factors that may influence incident rates and incident detection rates. The subsections of the central I-4 corridor were grouped by geometric characteristics including horizontal alignment (straight or curved) and vertical alignment (upgrade, level, or downgrade); and also by presence of ramps (on-ramps, off-ramps, or none). It was found that subsections with off-ramps have significantly higher incident rate and incident detection rate than subsections with on-ramps or with no ramps. It was also found that upgrade subsections have significantly higher incident rate than level or downgrade subsections. However, no significant difference in incident detection rate was found between these subsections. Based on the study results and to improve performance of incident detection algorithms on I-4, the subsections were regrouped by two factors: horizontal alignment and presence of ramps.