Protected bike lane retrofit via lane-width reallocation
RFT-CDR-07 CorridorProtected bike lane retrofit via lane-width reallocation
Overview
This is the lightest-touch of the three protected bike lane retrofits. AASHTO's Green Book allows narrower vehicle lanes, down to 10 feet, in many contexts, and a four-lane arterial with turn lanes can often be restriped during routine maintenance to include a buffer and a physically separated bike lane without touching lane count or parking at all.1
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.
Are Streets Too Complicated Now?
Asks whether today's proliferation of lines, signals, and lane types on streets is overcomplication or a needed response to modern demands, a question that runs directly through CS's Element-scale catalog and the density-tiered Corridor retrofit paths this video is tagged to.
Dutch-style intersection design: bike-friendly
Shows the protected-intersection design vocabulary, continuous cycle tracks, corner refuge islands, separated signal phasing, that underpins CS's Protected Intersection pattern and the Corridor retrofit paths built around it.
Where this leads: Target patterns
Bike Highway / Greenway (COL-BHG-04), Default (Standard Collector) (COL-DEF-01) with Protected Bike Lane / Cycle Track (ELM-PBL-37)
Applicability and thresholds
Most applicable where existing lanes are wider than required for safe operation at the corridor's design speed, giving enough recoverable width to build a genuine physical buffer rather than a painted line alone.
Evidence and effectiveness
FHWA identifies planned road diets and similar retrofits of higher-speed roads as prime opportunities to add separated bike lanes, since the same width analysis that supports a lane diet or road diet also identifies the space available for a buffer and protected lane.2
Getting it built
Restriping-based, so it can move through the full construction spectrum starting from paint and flexible delineators at the demonstration or pilot stage, before committing to permanent curb or planter-based separation. See Construction Methodology & The Build Spectrum.
Who can move this
Usually a city or county public works decision, achievable through routine restriping maintenance in many cases. See Legal & Planning Mechanisms.
Related retrofit strategies
Protected bike lane retrofit via lane removal (RFT-CDR-08), Protected bike lane retrofit via parking reduction (RFT-CDR-09) (the other two approaches to the same underlying goal, distinguished by where the recovered width comes from)