Winnipeg Assigns SPFs and Network Screening to Fireseeds North Infrastructure

The City of Winnipeg has awarded an assignment to Fireseeds North Infrastructure to develop safety performance functions (SPFs) and network screening protocols for its regional street network.

Winnipeg will join a select group of cities in Canada that have adopted the most rigorous possible approach to identifying sites with potential for safety improvement, a key step in an aggressive, quantitative road safety management program. These methods have the support of TAC and AASHTO publications and are considered the state-of-the-art in road safety.

A variety of approaches have historically been used for network screening:

1. Collision Counts
2. Collision Rates
3. Proportional Analysis
4. SPFs and Empirical Bayes Network Screening

The first three methods are certainly the easiest but suffer a number of limitations because collision counts contain a significant degree of random variability, they are related to exposure, and the relationship is non-linear. The 4th method is the state-of-the-art method and effectively removes these limitations to answer the question - "Which sites are truly 'off-the-safety-curve'  and hence have the most potential for safety improvement?"  The tools can also support answering many other questions such as the expected benefit of proposed countermeasures, and retrospective evaluations of past countermeasure effectiveness through before and after studies (answers to these questions cannot be reliably given without these tools).

Fireseeds North possesses the required in-house modelling and road safety expertise to develop these tools and is proud to support the City of Winnipeg in taking leadership steps to adopt state-of-the art road safety tools as part of its commitment to a safe transportation system for its citizens.