--- title: "Five-plus lane reallocation" url: "https://commonwaysystem.org/retrofits/corridor/five-plus-lane-reallocation/" id: "RFT-CDR-02" description: "Reduces the through-lane count on a roadway of five or more lanes, applying road diet principles at a larger scale than the standard four-to-three conversion." updated: "2026-10-18" --- RFT-CDR-02 # Five-plus lane reallocation Reduces the through-lane count on a roadway of five or more lanes, applying road diet principles at a larger scale than the standard four-to-three conversion. ## Strategy viewer Illustration in progress No illustration of Five-plus lane reallocation has been made yet. Interactive views are planned for every pattern and Retrofit Strategy. ## Overview Wider roadways, five lanes and up, carry enough volume and turning complexity that a straightforward four-to-three conversion doesn't apply directly. This strategy still removes excess through capacity and adds or widens a center turn lane, but requires more careful traffic analysis and often a phased approach, since five-lane-and-larger corridors typically carry higher volumes and more conflicting turning movements than the classic road diet case. ## Related Media The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself. 5 items - Aligned ### [The Dutch Solution for Safer Sidewalks - Continuous Sidewalks](https://www.youtube.com/watch?v=9OfBpQgLXUc) Not Just Bikes Shows the same sidewalk-continuity concept behind Continuous Sidewalk / Raised Junction in practice: the roadway rises to meet the sidewalk at a crossing, rather than the sidewalk dropping to meet the road, so geometry itself signals the priority shift. MED-001 - Aligned ### [What Happens If You Remove a Highway?](https://www.youtube.com/watch?v=EDp3JIXvOjY) Streetcraft The video looks at cities that removed urban highways, from Rochester's Inner Loop to Seattle's Alaskan Way Viaduct, and what replaced them. It is a real-world case for the Commonway System's road diet and corridor reallocation strategies. MED-034 - Aligned ### [Rochester gave up on a highway and filled it in. Should Baltimore?](https://www.thebanner.com/community/transportation/rochester-inner-loop-highway-removal-project-KA3KUYYNT5DO5KRAZIPQHCXZSQ/) The Baltimore Banner This long-form report traces Rochester's Inner Loop East removal, which turned a sunken expressway trench into homes, a bike path, and a boulevard. It is a deep single-city case for the Commonway System's highway-removal reasoning and corridor reallocation strategies. MED-056 - Aligned ### [How Money for Highways Could Have Built 36 Paris Metros (Ep 590)](https://usa.streetsblog.org/2026/08/20/talking-headways-podcast-how-money-for-highways-could-have-built-36-paris-metros) Talking Headways The episode covers a data project mapping the tax base and land value that urban freeways stripped from 142 American cities. It documents the costs behind the Commonway System's skepticism of urban highway building. MED-063 - Aligned ### [America's deadliest road, explained](https://www.youtube.com/watch?v=0-nthHT-J1k) Vox Vox examines a one-kilometer stretch of US-19 in Florida, the deadliest of 60 pedestrian-fatality hotspots in a national study, and shows how eight lanes, 45 mph speeds and crossings nearly a kilometer apart make deaths predictable rather than accidental. It is a vivid case study of the Stroad problem and of the crosswalk, signal, driveway and lane-removal fixes the Commonway System specifies. MED-107 [See all 5 in the Media Gallery](https://commonwaysystem.org/media/?for=RFT-CDR-02) ## Where this leads: Target patterns - [Default (No Parking, No Direct Access)](https://commonwaysystem.org/patterns/arterials/default.md) (ART-DEF-01) - [Boulevard](https://commonwaysystem.org/patterns/arterials/boulevard.md) (ART-BLV-02) ## Applicability and thresholds Evaluated specifically for roadways with five or more lanes in NCHRP-adjacent research, distinct from the four-to-three case. Sight-distance and conflict-point improvements follow the same underlying mechanism as a standard road diet, but volume thresholds run higher given the additional capacity these corridors typically carry. ## Evidence and effectiveness Research on five-lane-and-larger road diet projects documents conflict-point reduction and improved sight distance for turning drivers, using the same two-stage reasoning as smaller road diets: fewer lanes to scan, and a dedicated turn lane separating through and turning movements.[1] ## Getting it built Can move through the construction spectrum, though the larger scope, more lanes, more signal coordination, more turning-movement analysis, makes a formal pilot or quick-build stage more valuable here than on a simple four-to-three conversion. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md). An Intersection Control Evaluation is worth considering where the corridor's intersections will also see a change in turn-lane configuration. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md). ## Who can move this Typically a city or county transportation department decision, though the larger scope and often-higher-classification roadway makes state DOT coordination more likely than with a simple four-to-three road diet. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md). ## Related retrofit strategies - [Four-to-three lane road diet](https://commonwaysystem.org/retrofits/corridor/four-to-three-lane-road-diet.md) (RFT-CDR-01) (the smaller-scale equivalent this strategy extends) ## References 1. Evidence-based ["An Evaluation of 'Road Diet' Projects on Five Lane and Larger Roadways," transportation research summary distributed via NACTO.](https://nacto.org/wp-content/uploads/An-Evaluation-of-Road-Diet-Projects-on-Five-Lane-and-Larger-Roadways.pdf) 2. Legal / regulatory [Federal Highway Administration, "Road Diets (Roadway Reconfiguration)," Proven Safety Countermeasures, FHWA-SA-12-013.](https://highways.dot.gov/safety/proven-safety-countermeasures/road-diets-roadway-reconfiguration)