Performance Measurement Using IRI and Collision Rates in the Province of Alberta

The major objective of every highway agency in Canada is to provide a safe and reliable road network. Road safety is commonly evaluated by number of collisions while different performance measures are employed for evaluating the reliability and performance of roads. The International Roughness Index (IRI) is a widely used performance measure in Canada and Internationally. It is calculated from direct profile measurement of the pavement wheel paths and translated into metres per kilometre. In 1999, the Province of Alberta tied its performance publicly to a rolling three year target IRI that was tabled on the floor of the legislature. Subsequent annual business plans refer to the IRI and rehabilitation programs are developed on the basis of threshold values of IRI that are defined as good (<1.5), fair (1.5-1.9) or poor (>1.9). In this study, the definition of `good' (equal to IRI<1.5 in the Province of Alberta) is tested against the public’s perception using a survey tool. At selected sites in the Province, the driving public was asked about their opinion about the condition of the highway. Over 300 surveys were collected and the correlation between public perception and IRI was drawn using t-test and Psychometric Scaling Analysis. According to the results, Alberta Transportation threshold values of IRI do not match the road users' opinion and a new set of threshold values were suggested. The other part of this study evaluates the relationship between the number of collisions and IRI to estimate any measurable relationship between these two measures. The relationship between IRI and number of collisions is evaluated to see if number of collisions increases/decreases as a function of IRI, while all other characteristics of roads and traffic remains unchanged. Therefore, this study tried to fundamentally investigate and demonstrate a methodology that can consistently, objectively and robustly link IRI to road safety and work towards the development of a decision support tool for estimating the potential safety issues on the road network. The result showed that IRI can be used as a surrogate for safety and the number of collisions increase when the IRI value of the road increases.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Discipline thesis:degree_discipline

Civil Engineering

Grantor dc:publisher.institution

Graduate Studies

Year dc:date.issued

2014

Author dc:creator

• Sharif Tehrani, Saleh

Advisor dc:contributor.advisor

• Cowe Falls, Lynne

• Engineering--Civil

Statement dc:rights

• University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.

Language dc:language.iso

eng

DOI

http://dx.doi.org/10.11575/PRISM/27297

OAI identifier oai:identifier

oai:ucalgary.scholaris.ca:11023/1416