A Study on the Relationship Between Asset Condition and Safety on Primary Roads in Iowa

Abstract

<p>Incorporating safety performance measures into asset management can assist agencies to manage their aging assets efficiently and improve system-wide safety. Past research has revealed the relationship between individual asset performance and safety, but the relationship between combined measures of operational asset condition and safety performance has not been explored.</p> <p>This study investigates the effect of pavement marking retroreflectivity and pavement condition on safety in a multi-objective manner. Data on one-mile segments for all Iowa primary roads from 2004 to 2009 period were collected from the Iowa Department of Transportation and integrated by linear referencing. An Asset Condition Index (ACI), with a range of 1 to 3, was developed for the road segments by scoring and weighting individual components. Statistical models were then developed to estimate the relationship between ACI and expected number of crashes, while controlling for exposure. Finally, alternative treatment strategies for pavements and pavement markings were evaluated by benefit-cost ratio analysis, considering related treatment costs and safety benefits. Results indicated that minor rehabilitation and durable material marking have the highest B/C ratio within one year after implementation. And in terms of five years after treatments, a decision making matrix of ACI ranges versus treatment alternatives was developed. The same recommendation holds for segments with ACI higher than 2.0. For segments with ACI lower than 1.5, major rehabilitation and tape marking are recommended.</p>