--- title: "Chicago crash injury severity and injured-person counts" description: "Read Chicago crash severity and person-count fields separately. Use synthetic examples to document totals, unknown injury information, and denominators" canonical: "https://scalewithsearch.com/articles/chicago-crash-injury-severity-person-counts" --- ## Site navigation - [Scale With Search](https://scalewithsearch.com/) - Services - Services - [AI systems](https://scalewithsearch.com/ai-systems) - [Site build](https://scalewithsearch.com/work#site-build) - [Whole website fix](https://scalewithsearch.com/work#whole-website-fix) - [Content library with SEO](https://scalewithsearch.com/work#content-library) - [Working session](https://scalewithsearch.com/audit) - Start here - [Send your brief](https://scalewithsearch.com/work#send-your-brief) - [Example scope](https://scalewithsearch.com/work#review-the-example-scope) - [Prices and terms](https://scalewithsearch.com/work#prices-and-terms) - Industries - Real estate - [Real estate agents and teams](https://scalewithsearch.com/for/real-estate) - [Platforms, ownership, and IDX](https://scalewithsearch.com/for/real-estate/real-estate-website-platforms-ownership-idx) - [Search, content, and AI](https://scalewithsearch.com/for/real-estate/real-estate-search-content-ai) - [Inquiries, campaigns, and handoffs](https://scalewithsearch.com/for/real-estate/real-estate-website-inquiries-campaigns-handoffs) - [Buyer, seller, and local pages](https://scalewithsearch.com/for/real-estate/real-estate-buyer-seller-local-resources) - [Rules, privacy, and trust](https://scalewithsearch.com/for/real-estate/real-estate-website-rules-privacy-trust) - Browse by business - [Trades and home services](https://scalewithsearch.com/for/#group-trades) - [Health, wellness, and animal care](https://scalewithsearch.com/for/#group-practices) - [Law, finance, and IT](https://scalewithsearch.com/for/#group-professional) - [Marketing and SEO agencies](https://scalewithsearch.com/for/#group-agencies) - [Shops and manufacturers](https://scalewithsearch.com/for/#group-manufacturing) - [Restaurants, shops, studios, and nonprofits](https://scalewithsearch.com/for/#group-local-services) - Chiropractic practices - [Chiropractic and wellness practices](https://scalewithsearch.com/for/chiropractic-and-wellness-practices) - [Chiropractic and physical therapy clinics](https://scalewithsearch.com/for/chiropractic-and-physical-therapy-clinics) - [All industries](https://scalewithsearch.com/for/) - Resources - Free tools - [AI readiness check](https://scalewithsearch.com/check) - [Free tools](https://scalewithsearch.com/tools/) - [Free Starter Kit](https://scalewithsearch.com/kit/business-memory-starter-kit.zip) - Guides - [AI-native library](https://scalewithsearch.com/ai-native) - [Industry intelligence](https://scalewithsearch.com/intelligence) - [Office job guides](https://scalewithsearch.com/guides/) - [Business memory](https://scalewithsearch.com/articles/business-memory-for-ai-agents-guide) - [Agent governance](https://scalewithsearch.com/articles/ai-agent-governance-guide-small-business) - [Migration and ownership](https://scalewithsearch.com/articles/leaving-vendor-ai-memory-guide) - Articles - [All articles](https://scalewithsearch.com/articles/) - [What changed](https://scalewithsearch.com/changes/) - About - Evidence - [Proof](https://scalewithsearch.com/proof) - Scale With Search - [About](https://scalewithsearch.com/about) - [How it works](https://scalewithsearch.com/how-it-works) # Chicago crash injuries: distinguish the most severe category from the number of people A crash with three injured people remains one crash. A crash-level severity label describes the most severe injury recorded among those involved. It does not tell a firm researcher how many people sustained that injury category. Keep two questions separate in an aggregate research note: how many crash records meet the filter, and how many reported injured persons those records contain. Then state which records have usable information. An unknown value needs its own explanation before anyone interprets a total. The [personal injury firm overview](/for/personal-injury-law-firms) covers the firm's wider information responsibilities. The [public-evidence intelligence guide](/intelligence/personal-injury-law-firms) introduces aggregate crash research. This worksheet addresses the measurement decision behind that research, without identifying incidents or people. ## Start with the publisher's unit of observation Chicago describes this source as information about traffic crashes on city streets within city limits and CPD jurisdiction. Records enter the portal when reports are finalized or amended. Its description excludes crashes where another police agency responds, including typical interstate cases. [Chicago dataset description, checked October 28, 2026](https://data.cityofchicago.org/Transportation/Traffic-Crashes-Crashes/85ca-t3if). Consequently, label an aggregate as a count of records in this published source. Do not label it every collision in Chicago. Keep the covered reporting system, geography, selected dates, and access date beside the number. The publisher says some districts have records from 2015, while citywide availability begins in September 2017. Avoid treating those early records as an equivalent citywide baseline. A firm comparing periods should establish a common coverage window before interpreting differences. [Chicago coverage description, checked October 28, 2026](https://data.cityofchicago.org/api/views/85ca-t3if.json). For this worksheet, the working unit is one eligible crash record. Person totals are measures attached to that unit. A person total can exceed the record count without indicating duplication or an arithmetic error. ## Separate the severity label from the person total The dictionary defines `most_severe_injury` as the highest injury severity sustained by someone involved in a crash. It defines `injuries_total` as persons reported with fatal, incapacitating, non-incapacitating, or possible injuries. The reporting officer determines those injury counts. [Chicago injury-field dictionary, checked October 28, 2026](https://data.cityofchicago.org/api/views/85ca-t3if.json). Use the category to group crash records by their recorded maximum severity. Use the numeric fields to describe reported persons. Counting records within a category and adding a person-count column answer different questions. For example, a synthetic crash might include one person with an incapacitating injury and two with possible injuries. Its maximum severity reflects the incapacitating injury. Its total injured-person count is three. Neither field establishes that all three people share the maximum category. Do not multiply a severity-category crash count by an assumed number of occupants. The source already provides person-count fields with specific meanings. An assumed multiplier adds information that the aggregate does not establish. ## Read the published injury-count categories Keep the original field names in the research worksheet. The following descriptions paraphrase the publisher's dictionary. They describe reported classifications, rather than independent medical findings. [Chicago person-count definitions, checked October 28, 2026](https://data.cityofchicago.org/api/views/85ca-t3if.json). | Field | What its count represents | Treatment in an injury summary | | --- | --- | --- | | `injuries_fatal` | Persons recorded with fatal injuries | Included in the published total definition | | `injuries_incapacitating` | Persons recorded with incapacitating or serious injuries | Keep this category separate when describing severity | | `injuries_non_incapacitating` | Persons recorded with evident injuries outside the fatal or incapacitating categories | Do not relabel as a clinical diagnosis | | `injuries_reported_not_evident` | Persons recorded with possible injuries | Preserve the possible-injury meaning | | `injuries_no_indication` | Persons recorded as having no injury | Excluded from the published injured-person total definition | | `injuries_unknown` | Persons whose injury status is unknown | Report separately from known injury categories | The published total therefore does not mean everyone involved. Adding no-indication and unknown counts to `injuries_total` would change the measure. If a separate analysis needs a broader person count, define and verify it independently. The linked IDOT manual explains the underlying reporting classifications. Its 2019 edition, instruction 30, distinguishes fatal, suspected serious, evident minor, possible, and no-apparent-injury classifications. Read the original descriptions before choosing public labels. [IDOT SR 1050 instruction manual, 2019, instruction 30](https://idot.illinois.gov/content/dam/soi/en/web/idot/documents/transportation-system/manuals-guides-and-handbooks/safety/illinois-traffic-crash-report-sr-1050-instruction-manual-2019.pdf). These descriptions help interpret the reporting vocabulary. They do not authorize a firm to assign a diagnosis, infer treatment, or decide a case's value from a table. ## Work through five synthetic crash records Every entry below is invented. The letters identify worksheet examples, not source identifiers. No real dates, locations, narratives, or victim information appear. | Synthetic example | Highest recorded category, in plain language | Reported injured persons | Unknown injury-status persons | | --- | --- | --- | --- | | A | Possible injury | 1 | 0 | | B | Incapacitating injury | 3 | 0 | | C | No injury indicated | 0 | 0 | | D | Unavailable in this exercise | Unavailable | 2 | | E | Non-incapacitating injury | 1 | 1 | Example B contains one person in the incapacitating category and two in the possible category. Its three injured persons do not become three incapacitating-injury crashes. Example E includes one reported injury and one person with unknown injury status. The exercise contains five eligible crash records. Three records have a positive reported injured-person total. Four records have a usable injured-person total. Their reported injured-person sum is five: one plus three plus zero plus one. Example D's total is unavailable. The sum of five is therefore a subtotal across four records with usable totals. It is not a complete injured-person total for all five records. The worksheet separately contains three persons with unknown injury status. Do not add those three unknown persons to the subtotal and call eight people injured. Also do not describe them as uninjured. Unknown status remains unknown until another authorized source establishes more information. The example illustrates a review convention, rather than a claim about actual missing values in Chicago's current data. No current completeness percentage was measured for this article. ## Put a denominator beside every percentage In the synthetic exercise, three of five eligible crash records have a positive usable injury total. That is 60 percent of eligible records with a recorded positive total. It does not establish the true injury share when one record's total is unavailable. A different calculation uses only the four records with usable totals. Three of four is 75 percent within that known-total subset. Both calculations have clear denominators. Neither should appear under the unqualified heading “injury rate.” The total of five reported injured persons across four usable records gives 1.25 reported injured persons per usable crash record. If the question concerns injury-positive crashes, five divided by three is about 1.67. Label that denominator separately. These are arithmetic illustrations. They provide no traffic exposure denominator, population comparison, or probability that a traveler experiences injury. Counts from this exercise also establish no demand for private counsel. Choose one measure for the main research question. Keep the supporting totals close enough that a reader can reconstruct it. A percentage without its numerator and denominator is an incomplete handoff. ## Check category totals without manufacturing certainty As a review step, compare each usable total with its four included injury-category counts. Keep no-indication and unknown counts outside that comparison. If fields disagree or a required value is missing, retain an exception rather than silently repairing the source. Record what the check did. For example: “Verified agreement where all included category counts were available; excluded incomplete comparisons from the reconciliation check.” State how many records that sentence covers. A blank numeric cell should not become zero through a spreadsheet default. A known zero and unavailable information describe different states. Preserve that distinction in the worksheet before creating a chart or summary. Apply that check to synthetic example B. Its fatal count is zero, its incapacitating count is one, its non-incapacitating count is zero, and its possible-injury count is two. The four included categories sum to three. That agrees with its reported injured-person total. If someone groups B under its highest severity, the crash count in that group rises by one. If someone sums incapacitating persons, the person count rises by one. If someone sums all reported injured persons, the total rises by three. Write those three effects separately in the review note. Now consider example E. Its one reported injury remains in the injured-person subtotal. The additional unknown-status person remains in a separate column. A record can therefore contribute a known injury and an unknown status without resolving the unknown person into either outcome. This distinction keeps the worksheet's information limits visible. Keep maximum-severity grouping independent of this arithmetic check. A correct person sum does not prove every category label is complete. A plausible category label does not prove the person sum is usable. If the research cannot resolve an inconsistency, publish a narrower aggregate with the limitation visible. Do not invent a corrected injury category to make a table balance. ## Keep geography and source revisions visible A map can introduce another denominator. Records with usable location information may be a subset of the records used for injury measurement. The companion [map-coverage worksheet](/articles/chicago-crash-map-missing-location-coverage) explains how to retain unmapped records in the coverage count. For example, a map of injury-positive records should state both its injury filter and its location eligibility rule. Avoid presenting its mapped count as the total injury-positive count without checking the remainder. Chicago says reports can receive later amendments. A research note should therefore preserve its access date and source snapshot reference. Two researchers may inspect different versions of the published source. [Chicago amendment description, checked October 28, 2026](https://data.cityofchicago.org/api/views/85ca-t3if.json). When a total changes, distinguish a changed measurement rule from changed source records. Recalculate the agreed measures against the new source edition. Retain the earlier note so a reviewer can explain the difference. ## Use a short attorney-review worksheet Prepare the following worksheet before discussing an aggregate with the practice partner. The prompts are editorial controls for this research task, rather than publisher requirements. | Review item | What the note must contain | | --- | --- | | Source scope | Chicago dataset name, jurisdiction limits, and access date | | Period | Selected date field and start and end boundaries | | Crash denominator | Count of eligible records before location exclusions | | Severity grouping | Original field and documented category labels | | Person measure | Included injury-count categories and usable-record count | | Unknown information | Missing totals, unknown-status persons, and reconciliation exceptions | | Geography | Mapped subset and link to the separate coverage note | | Decision boundary | Broad research question and attorney review owner | Ask the reviewer to read one sentence aloud: “This number counts ___ among ___ during ___, using the source checked on ___.” If the blanks cannot be filled, the measure needs another pass. Store the accepted definitions with the aggregate. The [business-memory guide](/articles/business-memory-for-ai-agents-guide) explains why reusable source notes and corrections belong with the work. A later researcher should inherit the counting rule alongside the result. A bounded Scale With Search engagement can define this worksheet, the source boundary, and the acceptance checks. Describe the research question and the records the function may use in the written scope. [Define the scope](/work) Continue the website review: [AI-native injury law firms: the first functions to build](/articles/ai-native-injury-law-first-functions); [Chicago crash maps: keep missing locations in the coverage count](/articles/chicago-crash-map-missing-location-coverage); [Injury law firm AI rules: data, approvals, and spend](/articles/injury-law-firm-ai-rules-data-approvals-spend); [NHTSA complaint dates: separate the incident, receipt, and file addition](/articles/nhtsa-complaint-incident-received-added-dates); [NHTSA complaint counts: distinguish ODI references from component rows](/articles/nhtsa-complaint-odi-reference-component-row-counts); [Injury firm rebrand: map old website pages first](/articles/personal-injury-firm-rebrand-website-redirects); [AI gets your injury firm wrong: check the source facts](/articles/personal-injury-firm-wrong-ai-answer-facts); [Injury law firm virtual offices and Google profiles](/articles/personal-injury-law-firm-virtual-office-profile); [Injury website settlement calculators: check the promise](/articles/personal-injury-settlement-calculator-website-review); [Spanish injury firm pages: review the whole inquiry path](/articles/personal-injury-spanish-website-page-review); [Personal injury website leads: test the case review path](/articles/personal-injury-website-case-review-delivery); [Injury firm website fees: explain costs separately](/articles/personal-injury-website-contingency-fee-costs); [Injury website form spam: protect the real inquiry path](/articles/personal-injury-website-form-spam-control-review); [Injury website file uploads: define the private handoff](/articles/personal-injury-website-medical-record-upload-brief); [Personal injury settlement results on your website](/articles/personal-injury-website-settlement-results); [Injury website thank-you pages: keep the receipt plain](/articles/personal-injury-website-thank-you-page-privacy). [personal injury law firms](/for/personal-injury-law-firms): website and search resources. ## Related: personal injury law firms - [Chicago crash maps: keep missing locations in the coverage count](/articles/chicago-crash-map-missing-location-coverage) - [Injury law firm AI rules: data, approvals, and spend](/articles/injury-law-firm-ai-rules-data-approvals-spend) - [NHTSA complaint dates: separate the incident, receipt, and file addition](/articles/nhtsa-complaint-incident-received-added-dates) ---- ```text .|########||. .|########||. .|########||. |##||. .||##|. |##||. .||##|. |##||. .||##|. |#|. .|#|. |#|. .|#|. |#|. .|#|. |#| |#| |#| |#| |#| |#| .#| |#. .#| |#. .#| |#. .#. .#| .#. .#| .#. .#| |#. .#| |#. .#| |#. .#| |# ...... #| |# ...... #| |# ...... #| .# ||#########| #| .# ||#########| #| .# ||#########| #| .#. |######||######|. .#. .#. |######||######|. .#. .#. |######||######|. .#. #. .##|###|##|#|######| .# #. .##|###|##|#|######| .# #. .##|###|##|#|######| .# || |##|#||||||||||||#||#| || || |##|#||||||||||||#||#| || || |##|#||||||||||||#||#| || # |#||||||||||||||||||||#| #. # |#||||||||||||||||||||#| #. # |#||||||||||||||||||||#| #. || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || # .#||||||||||||||||||||||||#| # # .#||||||||||||||||||||||||#| # # .#||||||||||||||||||||||||#| # || ....|||#||||||##|#|||#|#||##||||....|. || || ....|||#||||||##|#|||#|#||##||||....|. || || ....|||#||||||##|#|||#|#||##||||....|. || #. . ....|# ....#||| ||| .#||| ....#. .# #. . ....|# ....#||| ||| .#||| ....#. .# #. . ....|# ....#||| ||| .#||| ....#. .# # . ||||#| .#####|| . .#| .#||| ||||# #. # . ||||#| .#####|| . .#| .#||| ||||# #. # . ||||#| .#####|| . .#| .#||| ||||# #. .| ||||| #. |#|||||. || #. |#||. .||||| || .| ||||| #. |#|||||. || #. |#||. .||||| || .| ||||| #. |#|||||. || #. |#||. .||||| || || |.... #. ....|#. |. ...|. ....|| || || |.... #. ....|#. |. ...|. ....|| || || |.... #. ....|#. |. ...|. ....|| || #. .||||||##||||||##||####|||||||#||||||#| .# #. .||||||##||||||##||####|||||||#||||||#| .# #. .||||||##||||||##||####|||||||#||||||#| .# # .||####|###########################|. # # .||####|###########################|. # # .||####|###########################|. # # .#||||||.#.|| # |. ..# #| #|||||#| # # .#||||||.#.|| # |. ..# #| #|||||#| # # .#||||||.#.|| # |. ..# #| #|||||#| # # .#|||||| .. |# ## |#| ...#|#|||#| # # .#|||||| .. |# ## |#| ...#|#|||#| # # .#|||||| .. |# ## |#| ...#|#|||#| # # .#|||#|# .# .#| #| ##|.#..#|||||#| # # .#|||#|# .# .#| #| ##|.#..#|||||#| # # .#|||#|# .# .#| #| ##|.#..#|||||#| # # .#||||||############|######|||||#| # # .#||||||############|######|||||#| # # .#||||||############|######|||||#| # # |...||#||||||#||||#|#||||||#|||||#||| |.| # # |...||#||||||#||||#|#||||||#|||||#||| |.| # # |...||#||||||#||||#|#||||||#|||||#||| |.| # #. .. ||||# .|||##|. |#| .|| || .|||#. #| # .# #. .. ||||# .|||##|. |#| .|| || .|||#. #| # .# #. .. ||||# .|||##|. |#| .|| || .|||#. #| # .# || | ...|| ...##| | #| .|. |. ##### .. .| || || | ...|| ...##| | #| .|. |. ##### .. .| || || | ...|| ...##| | #| .|. |. ##### .. .| || || ||||| || ||||#| . |. |. |#. ||||| |#| || || || ||||| || ||||#| . |. |. |#. ||||| |#| || || || ||||| || ||||#| . |. |. |#. ||||| |#| || || .# |.....#|....|#.||||.|||##.|#|....||.#||.#. #. .# |.....#|....|#.||||.|||##.|#|....||.#||.#. #. .# |.....#|....|#.||||.|||##.|#|....||.#||.#. #. #.|||||||#############################| ||| .# #.|||||||#############################| ||| .# #.|||||||#############################| ||| .# || ##||#||#||||||#||#||#||#||##. || || ##||#||#||||||#||#||#||#||##. || || ##||#||#||||||#||#||#||#||##. || # .#|||||||||#||#|||||||||||#| # # .#|||||||||#||#|||||||||||#| # # .#|||||||||#||#|||||||||||#| # || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || || |#||||||||||||||||||||||#| || .# |#||||||||||||||||||||#| #. .# |#||||||||||||||||||||#| #. .# |#||||||||||||||||||||#| #. || |#||||||||||||||||||#| || || |#||||||||||||||||||#| || || |#||||||||||||||||||#| || #. .######|#|#########| .# #. .######|#|#########| .# #. .######|#|#########| .# .#. |#####||||#####| .#. .#. |#####||||#####| .#. .#. |#####||||#####| .#. |# ||########|| #. |# ||########|| #. |# ||########|| #. |# ...... #| |# ...... #| |# ...... #| |#. .#| |#. .#| |#. .#| |#. .#. |#. .#. |#. .#. .#| |#. .#| |#. .#| |#. |#| |#| |#| |#| |#| |#| .|#|. .|#|. .|#|. .|#|. .|#|. .|#|. |##||. .||##| |##||. .||##| |##||. .||##| .||########||. .||########||. .||########||. 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