Climbing and Passing Lane Prioritization Study
Climbing and Passing Lane Prioritization Study
Project Overview
The 2025 Statewide Climbing and Passing Lanes Study updated the 2015 Climbing and Passing Lane Prioritization Study. This recent study developed a new priority list of locations for climbing and passing lanes that accounts for recent changes in traffic patterns on Arizona’s State Highway System (SHS) utilizing Arizona Department of Transportation (ADOT) current transportation datasets, improved performance evaluation strategies, and updated prioritization methodologies.
For the purposes of this study, climbing and passing lanes are defined as:
Climbing Lane
Additional lane on steep upgrades to facilitate the passing of trucks and slow-moving vehicles whose speed drops because of the sustained grade rather than a lack of passing opportunity over a long stretch of highway.
Passing Lane
Additional lane on highways to facilitate the passing of all types of slow-moving vehicles at locations other than sustained grades where passing opportunities are unavailable or very limited over a long stretch of highway.
Completed 2015 - Passing and climbing lanes provide additional lanes for vehicles to safely pass other vehicles while maintaining speeds. Implementing passing and climbing lane projects provides traffic operational and safety benefits at a cost that is far less than fully widening a highway. In an effort to enhance safety and mobility on Arizona's roadways, the ADOT worked on updating the 2003 Passing and Climbing Lanes Prioritization Study. This update further refines the identification and prioritization methodology previously utilized and develops a prioritized list of candidate locations that would provide the most benefit to the traveling public.