Key Takeaways
- Every Illinois crash report uses one code system. Police agencies statewide complete the same form, the SR 1050, and pick every code from two templates printed by the Illinois Department of Transportation (IDOT). The codes for cause run from 02 to 63, plus 99 for not applicable.
- The cause code is the officer’s judgment. IDOT defines the primary contributory cause as the factor most significant in causing the crash “as determined by officer judgment.” In 2025, the most common primary cause on Chicago injury crash reports was code 18, Unable to determine: 5,555 of 17,902 reports, or 31%.
- Unit 1 usually means the driver the officer blamed. IDOT tells officers to list the known or perceived at-fault vehicle as Unit 1, and the striking vehicle when fault is not evident.
- Injury codes describe what was visible at the scene. K is fatal, A is a suspected serious injury, B a suspected minor injury, C a possible injury and 0 no apparent injury. Pain without a visible wound is coded C, even when it turns out to be a fracture or a concussion.
- The report is not the final word on fault. Illinois Rule of Evidence 803(8) excludes police accident reports from the public-records exception, so the report generally cannot prove fault in court. Insurers still read it closely, so check every code and fix factual errors early.
An Illinois crash report is mostly boxes of numbers. To an insurance adjuster, those numbers are a fast summary of the crash: who the officer thought caused it, what each driver was doing, and how badly each person looked hurt. To most people holding their own report for the first time, they mean nothing.
This guide decodes the parts of the report that matter to an injury claim, using the code lists in IDOT’s own SR 1050 Instruction Manual for Law Enforcement Agencies. It covers the contributory cause codes, the injury codes, the driver action codes and the collision codes, then explains what the report can and cannot prove, and what to do if yours is wrong.
What Do the Codes on an Illinois Crash Report Mean?
The codes on an Illinois crash report come from the Illinois Traffic Crash Report, form SR 1050, the only crash report form approved under Illinois law for reporting crash investigations to IDOT. The investigating officer fills in each coded box using two IDOT coding templates. The two-digit contributory cause codes (02 to 63, plus 99) record what the officer believes caused the crash. The letter codes K, A, B, C and 0 record how badly each person appeared to be hurt. Other boxes record each driver’s action, the type of first crash, the weather, the road surface, lighting and more. None of these codes is a legal finding of fault.
Where the Codes Sit on Your Report
The SR 1050 has numbered fields, and IDOT’s manual tells officers which template each one comes from. The ones worth finding first:
- Primary and secondary cause (field 63). Near the lower right of the front page. One or two codes for the whole crash, not for each driver.
- Injury classification (field 30). One letter for every driver, passenger and pedestrian listed.
- Driver action (field 87). One code for each driver, in the coding boxes along the edge of the form.
- Type of first crash (field 91). One code describing how the crash began.
- Distracted (field 54). A yes or no box for each driver, with a number if yes.
Two more things to know before you read the codes. First, the unit numbers. IDOT’s manual says “Known or perceived vehicles at-fault should be entered as Unit 1,” and if the at-fault vehicle is not evident, the striking vehicle is Unit 1. Second, the report type. If anyone was hurt or a vehicle had to be towed because of crash damage, the officer must complete the entire form (IDOT calls this a Type B crash). Otherwise only the blue-shaded fields are required, so a property-damage-only report can be thin.
Contributory Cause Codes (Field 63)
These are the codes most people are looking for. IDOT defines the primary contributory cause as “the factor which is most significant in causing the crash, as determined by officer judgment,” and the secondary cause as the second most significant factor. The officer enters one or two codes for the whole crash.
| Code | Cause |
|---|---|
| 02 | Failing to yield right-of-way |
| 03 | Following too closely |
| 04 | Improper overtaking/passing |
| 05 | Driving on wrong side/wrong way |
| 06 | Improper turning/no signal |
| 07 | Turning right on red |
| 08 | Under the influence of alcohol/drugs (used when an arrest is made) |
| 10 | Equipment: vehicle condition |
| 11 | Weather |
| 12 | Road engineering/surface/marking defects |
| 13 | Road construction/maintenance |
| 14 | Vision obscured (signs, tree limbs, buildings, etc.) |
| 15 | Driving skills/knowledge/experience |
| 17 | Physical condition of driver |
| 18 | Unable to determine |
| 19 | Had been drinking (used when no arrest is made) |
| 20 | Improper lane usage |
| 21 | Animal |
| 22 | Disregarding yield sign |
| 23 | Disregarding stop sign |
| 24 | Disregarding other traffic signs |
| 25 | Disregarding traffic signals |
| 26 | Disregarding road markings |
| 28 | Failing to reduce speed to avoid crash |
| 29 | Passing stopped school bus |
| 30 | Improper backing |
| 32 | Evasive action due to animal, object, nonmotorist |
| 40 | Distraction from outside vehicle |
| 41 | Distraction from inside vehicle |
| 43 | Distraction: other electronic device (navigation device, DVD player, etc.) |
| 44 | Texting |
| 45 | Cell phone use other than texting |
| 50 | Operating vehicle in erratic, reckless, careless, negligent or aggressive manner |
| 60 | Motorcycle advancing legally on red light |
| 61 | Bicycle advancing legally on red light |
| 62 | Obstructed crosswalks |
| 63 | Related to bus stop |
| 99 | Not applicable |
What a few of the codes really tell you
- 18, Unable to determine. The officer did not commit to a cause. That is common: the City of Chicago’s crash data shows code 18 as the primary cause on 31% of 2025 crash reports with an injury, more than any actual driving error. A code 18 leaves fault open, which cuts both ways. It does not hurt you, but it does not help you either, so your own evidence carries more weight.
- 08 versus 19. Both point at alcohol or drugs. Code 08 is used when an arrest is made, and code 19, Had been drinking, when there is no arrest. Either one on the other driver’s side of the report is significant.
- 44 and 45. Texting and other phone use. If the report codes either one against the other driver, raise it early: phone records are strong evidence of distraction, and they are easier to secure before a claim drags on.
- 60 and 61. These exist because 625 ILCS 5/11-306(c)(3.5) lets a motorcycle or bicycle proceed through a steady red light that has not changed after at least 120 seconds, because of a malfunction or because the signal failed to detect it, after stopping and yielding to traffic facing a green. If you ride and the other driver blamed you for running a red, check whether the officer used one of these codes.
Injury Codes: K, A, B, C and 0 (Field 30)
Every person listed on the report gets one injury classification, the most severe injury the officer observed or was told about. IDOT’s manual gives each letter a definition.
| Code | What it means on the report |
|---|---|
| K | Fatal injury: any injury that results in death after the crash, including a death after the report was first filed |
| A | Suspected serious (incapacitating) injury: for example a broken or distorted arm or leg, a crush injury, a severe laceration, a suspected skull, chest or abdominal injury, significant burns, unconsciousness when taken from the scene, or paralysis |
| B | Suspected minor (nonincapacitating) injury: an injury evident at the scene, such as a lump on the head, abrasions or minor cuts |
| C | Possible injury (reported, not evident): a claimed injury with no visible wound, such as complaint of pain, limping, nausea or a momentary loss of consciousness |
| 0 | No apparent injury: no physical evidence of injury and no reported change in normal function |
The important word in every definition is “suspected” or “evident.” The officer codes what they can see and what you say at the scene, often minutes after the crash and before any medical exam. Whiplash, a herniated disc or a concussion is often coded C, and an injury that starts hurting that night can be coded 0. That code does not cap your claim. What proves the injury is the medical record, which is why getting checked promptly matters (our guide to what to do after an accident covers it). If you did tell the officer you were hurting, the C code is useful evidence that you reported pain at the scene.
Driver Action Codes (Field 87)
The cause codes describe the crash. The driver action code describes each driver separately, so this is where the report says what the officer thought you did and what the other driver did.
| Code | Driver action |
|---|---|
| 1 | None |
| 2 | Failed to yield |
| 3 | Disregarded control devices |
| 4 | Too fast for conditions |
| 5 | Improper turn |
| 6 | Wrong way/side |
| 7 | Followed too closely |
| 8 | Improper lane change |
| 9 | Improper backing |
| 10 | Improper passing |
| 11 | Improper parking |
| 12 | License restriction |
| 13 | Stopped school bus |
| 14 | Emergency vehicle on call |
| 15 | Evading police vehicle |
| 16 | Other |
| 44 | Texting |
| 45 | Cell phone use other than texting |
| 46 | Overcorrected |
| 75 | Failure to move over for stationary emergency vehicle |
| 99 | Unknown |
A 1, None, next to your unit is what you want to see. If your unit carries a driver action code and you disagree with it, that is the code to address first, because an adjuster will read it as the officer’s view of your share of fault.
Type of First Crash and Other Codes Worth Checking
The type of first crash (field 91) records how the crash began, not the worst thing that happened in it. Codes 1 to 8 are single-vehicle crashes: 1 pedestrian, 2 pedalcyclist, 3 train, 4 animal, 5 overturned, 6 fixed object, 7 other object and 8 other noncollision. Codes 9 to 18 are crashes between vehicles: 9 parked motor vehicle, 10 turning, 11 front to rear, 12 sideswipe same direction, 13 sideswipe opposite direction, 14 front to front, 15 angle, 16 rear to side, 17 rear to rear and 18 rear to front. IDOT tells officers to choose by each vehicle’s intended direction of travel before the crash, not the angle at impact, so a T-bone crash at a light is normally a 15 (angle) and a rear-end crash an 11.
A few more boxes can matter to a claim:
- Distracted (field 54). If the officer marked a driver distracted, the number says how: 1 cell phone hands-free, 2 cell phone handheld, 3 texting or email, 4 other electronic device, 5 other inside the vehicle, 6 other outside the vehicle, 7 inattentive or daydreaming, 9 unknown.
- Apparent physical condition (field 83). For each driver: 1 normal, 2 impaired by alcohol, 3 impaired by drugs, 7 had been drinking, 8 fatigued or asleep, 13 impaired by alcohol and drugs, among others.
- Vehicle use (field 98). Code 25 is rideshare and 18 is taxi or for hire. If an Uber or Lyft was involved, the app phase at the time of the crash decides which insurance applies; see our guide to rideshare insurance coverage in Illinois.
- Insurance company and policy number (fields 55 to 57). “NONE” or a missing policy for the other driver points toward your own uninsured motorist coverage.
Does the Crash Report Decide Who Was at Fault?
No. The report records one officer’s judgment, usually formed at the scene from what the drivers and any witnesses said. It is not a finding by a court, and Illinois evidence rules treat it with suspicion. Illinois Rule of Evidence 803(8), the hearsay exception for public records, expressly excludes “police accident reports,” and the Supreme Court’s committee commentary notes that Supreme Court Rule 236, the business records rule for civil cases, excludes them as well. So in a lawsuit the report generally cannot be admitted to prove who caused the crash, although the officer can testify about what they personally saw.
Fault in an Illinois injury case is decided under the state’s modified comparative fault rule. Under 735 ILCS 5/2-1116, you can recover damages as long as your share of the fault is not more than 50%, and your damages are reduced by your percentage. A judge or jury sets that percentage from all the evidence, not from the codes on the report. Our guide to Illinois fault-based car accident law explains how the split works.
That said, the report matters in practice. Most injury claims settle without a trial, and the adjuster deciding what to offer reads the cause codes, the driver action codes and the unit numbers before almost anything else. A report that blames you, or that leaves fault at code 18, means your photos, witness names and medical records have to carry the claim.
What to Do If Your Crash Report Is Wrong
Errors are common. In Chicago, about half of all crash reports are taken at a police district station from the drivers themselves rather than at the scene, according to the city’s description of its crash data, and officers at a busy scene are working fast.
- Get the full report, not a summary, and read every coded box against the tables above.
- Sort errors into facts and opinions. A wrong name, plate, insurer, policy number, street, direction of travel or injury code for a person who was taken to the hospital is a factual error. The cause code and driver action codes are the officer’s judgment.
- Ask the investigating agency to correct factual errors in writing. Include the report number and proof, such as your insurance card, photos of the scene or an ambulance record. IDOT’s manual tells agencies to use the SR 1050A form to amend a report already sent to IDOT, and the City of Chicago notes that the reporting officer may amend a report when new information comes in.
- For a disputed judgment call, ask to add your statement. Officers rarely change their conclusion about cause, but new evidence, such as an independent witness or video, is the best reason for them to take another look.
- Preserve the evidence the report missed. Dashcam and doorbell video, business security footage and the other driver’s phone records can disappear within weeks.
How to Get a Copy of Your Illinois Crash Report
Ask the agency that investigated the crash: the city police department, the county sheriff or the Illinois State Police. IDOT will not provide one. Its manual notes that “Illinois law does not allow IDOT to provide copies of crash reports,” while the investigating agency may furnish copies, and 625 ILCS 5/11-412 keeps IDOT’s copies confidential. Under 625 ILCS 5/11-416, the Illinois State Police charge $5 for a copy of a report it investigated, or $20 if a crash reconstruction officer or team investigated, and local agencies can charge no more than those amounts. Officers must send the report to IDOT within 10 days after the investigation, so allow a week or two. For the reporting deadlines that apply to drivers, see how long you have to report an accident in Illinois, and for what the officer does at the scene, how police officers help after an accident.
When the Report Is Worth a Lawyer’s Look
A crash report that blames you, codes your injury as 0 or C when you went to the hospital, or leaves the cause at 18 is worth having a lawyer review before you give a recorded statement to any insurer. The same goes for crashes involving a pedestrian, a bicyclist, a motorcycle or a commercial truck, where the report’s codes are often disputed. Keep the deadline in mind: under 735 ILCS 5/13-202, most Illinois personal injury lawsuits must be filed within 2 years of the crash, and claims against a city, the CTA or another local government have shorter limits (see our guides to the Illinois statute of limitations and the Tort Immunity Act).
Our Illinois car accident lawyers review crash reports for injured drivers, passengers and pedestrians across the state, including in Chicago, Aurora, Naperville, Joliet, Rockford, Springfield, Peoria, Champaign, Elgin, Cicero, Elmhurst and Oak Brook.
Frequently Asked Questions
What do the numbers on an Illinois crash report mean?
The numbers are codes from the Illinois Traffic Crash Report, form SR 1050, which every police agency in the state uses. Officers pick each code from two coding templates printed by the Illinois Department of Transportation. The ones that matter most to an injury claim are the primary and secondary contributory cause (two-digit codes 02 to 63, or 99), the driver action code for each driver, the injury classification for each person (K, A, B, C or 0) and the type of first crash (1 to 18).
What does contributory cause code 18 mean on an Illinois crash report?
Code 18 means Unable to determine: the officer did not name a primary cause of the crash. It is common. In 2025, code 18 was the primary cause on 5,555 of the 17,902 Chicago Police crash reports involving an injury, about 31%. A code 18 does not mean nobody was at fault. It means fault was left for the insurers, and if necessary a court, to decide from the evidence.
Is Unit 1 on an Illinois crash report the at-fault driver?
Usually, but not by definition. IDOT’s SR 1050 Instruction Manual tells officers to list the known or perceived at-fault vehicle as Unit 1, and the striking vehicle as Unit 1 when fault is not evident. So being listed as Unit 2 is a good sign, but the unit numbers reflect the officer’s impression at the scene, not a legal finding of fault.
What does injury code C mean on an Illinois crash report?
C means possible injury: a person reported or showed signs of an injury, such as complaining of pain, limping or nausea, but no wound was visible at the scene. The scale runs K (fatal), A (suspected serious injury), B (suspected minor injury), C (possible injury) and 0 (no apparent injury). A C or 0 code reflects what the officer could see, so it does not limit a claim if a doctor later diagnoses a real injury such as a herniated disc or a concussion.
Can a police crash report be used as evidence in an Illinois lawsuit?
Generally not as proof of who caused the crash. Illinois Rule of Evidence 803(8) and Supreme Court Rule 236 both exclude police accident reports from the hearsay exceptions for public and business records, so the report itself usually cannot be admitted to prove fault. The officer can still testify about what they personally saw, and insurance adjusters read the report closely when they decide how to handle a claim.
Can I get an Illinois crash report changed if it is wrong?
You can ask. Contact the investigating agency, give the report number, and explain the error in writing with proof, such as your insurance card for a wrong policy number or photos for a wrong location. Agencies can amend a report already sent to IDOT using the SR 1050A form, and Chicago Police officers can amend a report when new information comes in. Factual errors are the easiest to fix; an officer is less likely to change a judgment call like the contributory cause.
How much does an Illinois crash report cost?
The Illinois State Police charge $5 for a copy of a crash report it investigated, or $20 if a crash reconstruction officer or team investigated it. Local police departments and sheriffs may charge no more than $5, or $20 for a reconstruction report. The fees are set by 625 ILCS 5/11-416.
How long does it take for an Illinois crash report to be filed?
An officer who investigates a reportable crash must send the written report to IDOT within 10 days after the investigation, under 625 ILCS 5/11-408. A crash is reportable if anyone is hurt or killed, or property damage exceeds $1,500 ($500 if any vehicle involved is uninsured). Ask the investigating agency for your copy rather than IDOT, which by law cannot release crash reports to the public.
Hurt in an Illinois Crash?
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Sources
- Illinois Department of Transportation, Illinois Traffic Crash Report SR 1050 Instruction Manual for Law Enforcement Agencies (2019 edition, last updated May 18, 2023): general information, reporting requirements, instructions 30, 54, 63, 83, 87 and 91, and Coding Templates 1 and 2.
- Illinois Vehicle Code, 625 ILCS 5: Sections 11-306 (traffic signals, including the motorcycle and bicycle red-light rule), 11-407 (immediate notice of crash), 11-408 (police to report crash investigations within 10 days), 11-412 (crash reports confidential) and 11-416 (copies and fees).
- Code of Civil Procedure, 735 ILCS 5: Sections 2-1116 (modified comparative fault) and 13-202 (two-year limit for personal injury).
- Illinois Supreme Court, Illinois Rules of Evidence, Rule 803(8) and the committee commentary on Supreme Court Rule 236.
- City of Chicago Data Portal, Traffic Crashes – Crashes (Chicago Police Department E-Crash records), crashes dated January 1 to December 31, 2025 with at least one injury, grouped by primary contributory cause. Retrieved October 15, 2026.
This article is general information about Illinois law and crash reporting, not legal advice, and reading it does not create an attorney-client relationship. The code lists come from IDOT’s SR 1050 Instruction Manual, and agencies that report electronically may display codes in a different layout. Deadlines and the effect of a crash report depend on the facts of each case, so please speak with a lawyer about your own situation as soon as possible.
