How to Read a Retrofit Strategy
Retrofit Strategies answer a different question than Patterns do. A Pattern describes what a street should be. A Retrofit Strategy describes how to move an existing street toward that destination. This page explains how each part of a Retrofit Strategy entry works.
If you haven't read How to Read a Pattern yet, start there first. Retrofit Strategies borrow several conventions from Patterns directly, and this page assumes you already know them.
#The ID card
Every Retrofit Strategy has an ID in the format RFT-SCALE-##, for example RFT-CDR-01.
- RFT marks this as a Retrofit Strategy, not a Pattern.
- SCALE is one of three values: CDR (Corridor), INT (Intersection), or NET (Network). This tells you what level the strategy operates at, a single street segment, a single intersection, or an area-wide network.
- ## is a sequential number within that scale. Numbers are never renumbered or reused, matching how Pattern IDs work.
The scale appears directly on the ID card, the same place Patterns display their own identifying information. There is no separate scale badge. If you're used to reading a Pattern's ID card, reading a Retrofit Strategy's works the same way.
Retrofit Strategies do not carry status badges (Recommended, Situational, Discouraged, and so on). A Pattern's badge tells you whether CS endorses that destination. A Retrofit Strategy isn't endorsed or discouraged in that sense, it's either applicable to your situation or it isn't. That judgment lives in the Applicability and thresholds section below, not in a badge.
#Overview
A short, word-lite explanation of what the strategy physically or procedurally involves. If you've never heard of a road diet or a Restricted Crossing U-Turn, this is where you find out what it actually is, in plain language, before anything else.
#Where this leads: Target patterns
Every Retrofit Strategy exists to move a street toward one or more destinations. This section lists the Pattern or Patterns this strategy typically produces. A four-to-three lane road diet, for instance, usually leads toward a Collector or Arterial pattern with added bike facilities, so that Pattern is listed and linked here.
This section is the mirror image of a Pattern page's own "Getting there: Retrofit path options" section, which lists the strategies that lead to that Pattern. Read together, the two sections let you navigate in either direction, start from where you are and find out where you could go, or start from a destination and find out how to get there.
#Applicability and thresholds
The conditions under which this strategy is actually appropriate. Traffic volume ceilings, existing lane count, context type, and similar thresholds live here. This is the section to read before proposing anything, since it tells you whether the strategy even fits your street.
Thresholds here are evidence-based and cited, not judgment calls. Where research gives a specific number, for instance a volume ceiling above which a road diet stops being appropriate, that number appears here with its source.
#Evidence and effectiveness
The measured outcomes: crash reduction percentages, safety findings, and other studied effects. Every citation carries its evidence-tier chip, Legal / regulatory Evidence-based Precedent-based, the same standard used across every citation sitewide.
#Getting it built
Two questions, answered briefly:
- Where does this strategy fall on the construction spectrum? Some strategies can move through demonstration, pilot, and quick-build stages before becoming permanent. Others, because of their scale or complexity, effectively require full capital construction from the start. This section says which, and links to the Guide's Construction Methodology & The Build Spectrum page rather than re-explaining the spectrum here.
- Does this strategy typically require a formal decision process first? Some strategies, particularly at the Intersection scale, are commonly preceded by an Intersection Control Evaluation or a Road Safety Audit. This section notes that and links to the Guide's Decision & Evaluation Processes page rather than re-explaining the process here.
#Who can move this
A compact note on jurisdiction and leverage. Not a full treatment of legal or funding mechanisms, just enough to tell you whether this is a city council conversation, a state DOT conversation, or something a neighborhood group can push for directly. Links out to Legal & Planning Mechanisms and Funding & Financing Mechanisms for the deeper detail.
This section exists because Retrofit Strategies, unlike Patterns, are things someone has to actually go do. Knowing what tool exists is only useful if you also know whose hands it's in.
#Related retrofit strategies
Some strategies belong to a family. The three approaches to retrofitting a protected bike lane, reallocating lane width, removing a lane, or reducing on-street parking, are distinct strategies with distinct tradeoffs, but they're solving the same underlying problem in different ways. This section cross-references the other members of that family so you can compare approaches before choosing one.
This section only appears when a genuine family relationship exists. It follows the same inclusion standard as a Pattern's Related patterns section: a stated relationship, a defined structural connection, or a genuinely non-obvious pairing, never inclusion just because two strategies happen to share a scale.
#References
Primary sources only, evidence-tier tagged, in the same citation format used throughout the site.
#The short version
If you remember nothing else from this page: a Pattern is a destination, a Retrofit Strategy is a path. Start with Where this leads if you're standing at a strategy and want to know what it produces. Start with Getting there if you're standing at a Pattern and want to know how to reach it. Everything else on a Retrofit Strategy page exists to help you judge whether that path is the right one for your street, and who needs to help you walk it.