Development of VSL Algorithms on I‐25 and I‐70 | TIM on I-70 | Development of Meaningful Metrics

APA Colorado Chapter


Friday, April 19, 2019
9:20 a.m. - 10:20 a.m. MDT

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Development of VSL Algorithms on I‐25 Gap Project and I‐70 West: Empirical examination of the relationship between flow/density, speed and crash rate on freeways in Colorado suggests that as flow/density increases crash rate initially remains constant until a certain critical threshold combination of speed and density is reached. Once this threshold is exceeded the crash rate rapidly rises. The rise in crash rate is explained by the fact that compression of flow without notable reduction in speed produces headways so small that it becomes very difficult or impossible to compensate for driver’s error to avoid a crash. It stands to reason that slowing traffic down in real time via displays on Variable Speed Limit (VSL) signs in advance of reaching this threshold have potential to  improve safety and travel time reliability. This presentation will explain how safety performance based VSL algorithms were developed for I‐25 Gap Project and I‐70 West.

Learning Objectives: 1) Understand Relationships between flow parameters and safety Development of Variable Speed Limit Algorithms; 2) Specifics of VSL algorithms development on I‐25 Gap Project and I‐70 West

Traffic incident Management on I-70 in Eastern Colorado: I‐70 in Eastern Colorado experiences crashes, Rollovers and wind events more than you would expect. I have taken over this section from Region 1 and have united the first responders on the local level to understand TIM's and to place these practices into actions.

Learning Objectives: 1) Buy in form the locals ‐ What's in it for me?; 2) Communication and collaboration ‐ the A ha moment!; 3) Safety and mobility of the first responders and the mobility of the Interstate

Development of Meaningful Metrics for Safety, Mobility, and Accessibility in the Era of Vision Zero: Vision Zero report cards often list various transportation improvements that address community objectives such as building curb ramps or projects that address cycling comfort. These types of efforts, albeit important, may not specifically ‘move the needle’ on crash numbers. This session will discuss how to report metrics for Vision Zero and create meaningful parallel programs to quantify mobility and accessibility objectives.

Learning Objectives: 1) Learn about Vision Zero efforts; 2) Learn about trends in Vision Zero programs that may not ‘move the needle’; 3)Learn about ways to capture and report important improvements to accessibility and mobility


Jake Kononov

Dr. Kononov is the founding Principal of DiExSys and is an internationally known expert in highway safety. Jake has over 30 years of experience in all aspects of highway and traffic engineering. As Principal of DiExSys he has provided Expert Advice, Policy Guidance, and Decision Support analysis on highway safety ... Read More

Rich Sarchet

Rich has over 20 years of transportation engineering experience at CDOT, with 15 of those years focused on safety and traffic operations. From 2011 through 2015 Rich worked as Region 3 Traffic Operations Engineer addressing multidisciplinary problems of safety and mobility unique to Western Colorado. He has evaluated hundreds of ... Read More

Larry Haas

Larry has been a CDOT traffic engineer for nearly 30 years. Traffic Incident management plays a big part in the mobility of the Region. It is my goal to get TIMP plans in place for the major highways in Region 4. Read More

Martina Wilkinson

Martina is the Assistant City Traffic Engineer with the City of Fort Collins. She has a bachelor’s degree in civil engineering from Colorado State University, and a master’s degree in traffic from the University of Washington in Seattle. In more than 25 years in the profession, she’s ... Read More

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