Start date: 01/01/10
End date: 12/31/10
About the research
Horizontal curves are over-represented, high-frequency, high-severity crash locations. Significant opportunities exist to mitigate these crashes through relatively low-cost safety improvements such as paved shoulders, rumble strips/stripes, and improved signing and delineation.
However, the presence of horizontal curvature is not captured as part of the Iowa crash report and the Iowa Department of Transportation (DOT)-maintained database of public roadways does not identify the locations of horizontal curvature. Therefore, it is currently difficult to identify the locations of curves systematically, and particularly high-crash curves and the characteristics of these curves.
The goal of this project was to expand the Iowa Department of Transportation (DOT) effort to systematically identify high-crash and potentially-problematic horizontal curves.
The primary objective of this project was to refine the previously-developed, preliminary, horizontal-curve database, allowing specific curve parameters to be extracted and evaluated system wide. This refinement facilitates identification of not only high-crash locations but candidate sites for low-cost safety improvements.
Secondary objectives include updating the high-crash curve list, evaluating the accuracy of the geometric parameter estimates and testing the sensitivity of safety performance to errors in curve parameters.
Report: Horizontal Curve Identification and Evaluation (897.88 kb pdf) September 2012
Sponsor(s): Iowa Department of Transportation