Race Control Messages

Overview

Race Control Messages (RCM) are official communications sent by race officials to teams about track status, flags, DRS availability, penalties, and incidents. These messages dictate the rules of engagement during the session and directly impact strategy decisions.

Race control messages are the official record of track conditions. They determine when drivers can overtake, when DRS is available, and when the session is under caution or stopped.

File Location

Race control messages are stored once per session:

Pre-Season Testing 2/Practice 3/rcm.json

Example:

Pre-Season Testing 2/Practice 3/rcm.json
Bahrain Grand Prix/Race/rcm.json
Monaco Grand Prix/Qualifying/rcm.json

Data Structure

The JSON file contains parallel arrays where each index represents one message:

{
  "time": ["2026-02-20T06:48:12.000000000", "2026-02-20T07:00:00.000000000", ...],
  "cat": ["Other", "Flag", "Drs", "CarEvent", ...],
  "msg": ["SESSION WILL START AT 09:00", "GREEN LIGHT - PIT EXIT OPEN", ...],
  "status": ["None", "ENABLED", "DISABLED", ...],
  "flag": ["None", "GREEN", "YELLOW", "RED", ...],
  "scope": ["Track", "Sector", "Driver", ...],
  "sector": ["None", "None", 11, ...],
  "dNum": ["None", "None", "44", ...],
  "lap": ["None", 5, 12, ...]
}

Field Reference

Core Message Information

time

array<string>

required

Timestamp when this message was issued by race control.Format: ISO 8601 timestamp
Example: ["2026-02-20T06:48:12.000000000", "2026-02-20T07:00:00.000000000", ...]

cat

array<string>

required

Category of the message being sent.Values:

"Other" - General session information
"Flag" - Flag-related messages (Yellow, Red, Green, etc.)
"Drs" - DRS status changes
"CarEvent" - Driver-specific events (penalties, unsafe release, etc.)

Example: ["Other", "Flag", "Drs", "CarEvent", ...]

msg

array<string>

required

Human-readable description of the event.Examples:

"GREEN LIGHT - PIT EXIT OPEN"
"YELLOW IN TRACK SECTOR 11"
"DRS ENABLED"
"RED FLAG - RACE SUSPENDED"
"CAR 44 - UNSAFE RELEASE"
"CHEQUERED FLAG"

Example array: ["SESSION WILL START AT 09:00", "GREEN LIGHT - PIT EXIT OPEN", ...]

status

array<string|null>

Additional context about the message state, depends on category.Common values:

"ENABLED" - DRS/feature enabled
"DISABLED" - DRS/feature disabled
"CLEAR" - Condition cleared
null - No specific status

Example: [null, "ENABLED", "DISABLED", "CLEAR", ...]

Flag Information

flag

array<string|null>

Type of flag being waved (if category is “Flag”).Values:

"GREEN" - Track clear, session active
"YELLOW" - Caution, hazard on track
"RED" - Session stopped
"CLEAR" - Previous flag condition cleared
"CHEQUERED" - Session ended
null - Not a flag message

Example: [null, "GREEN", "YELLOW", "CLEAR", "RED", ...]

Scope and Location

scope

array<string|null>

How wide the impact of this message is.Values:

"Track" - Entire circuit affected
"Sector" - Specific sector(s) affected
"Driver" - Single driver affected
null - Not applicable

Example: ["Track", "Sector", "Driver", ...]

sector

array<number|null>

Which mini-sector is affected (if scope is “Sector”).

The track is divided into 3 main sectors, each subdivided into 8 mini-sectors, giving 24 total mini-sectors (numbered 1-24).

Range: 1-24
Example: [null, null, 11, 12, null, ...]

dNum

array<string|null>

Driver number affected by the message (if scope is “Driver”).Format: String car number
Example: [null, null, "44", "1", "63", null, ...]

lap

array<number|null>

Which lap number this message refers to (context-dependent).Example: [null, null, 5, 12, null, ...]

Real Data Example

Here’s actual race control message data from Pre-Season Testing 2, Practice 3:

{
  "time": [
    "2026-02-20T06:48:12.000000000",
    "2026-02-20T07:00:00.000000000",
    "2026-02-20T09:11:03.000000000",
    "2026-02-20T09:11:25.000000000",
    "2026-02-20T09:13:18.000000000",
    "2026-02-20T09:13:20.000000000",
    "2026-02-20T09:16:01.000000000",
    "2026-02-20T09:16:10.000000000"
  ],
  "cat": [
    "Other",
    "Flag",
    "Flag",
    "Other",
    "Flag",
    "Flag",
    "Flag",
    "Other"
  ],
  "msg": [
    "PINK HEAD PADDING MATERIAL MUST BE USED",
    "GREEN LIGHT - PIT EXIT OPEN",
    "YELLOW IN TRACK SECTOR 11",
    "RED FLAG - RACE SUSPENDED",
    "TRACK CLEAR",
    "YELLOW IN TRACK SECTOR 11",
    "CLEAR IN TRACK SECTOR 11",
    "SESSION WILL RESUME AT 12:17"
  ],
  "status": [
    null,
    "ENABLED",
    null,
    null,
    "CLEAR",
    null,
    "CLEAR",
    null
  ],
  "flag": [
    null,
    "GREEN",
    "YELLOW",
    "RED",
    "CLEAR",
    "YELLOW",
    "CLEAR",
    null
  ],
  "scope": [
    "Track",
    "Track",
    "Sector",
    "Track",
    "Track",
    "Sector",
    "Sector",
    "Track"
  ],
  "sector": [
    null,
    null,
    11,
    null,
    null,
    11,
    11,
    null
  ],
  "dNum": [
    null,
    null,
    null,
    null,
    null,
    null,
    null,
    null
  ],
  "lap": [
    null,
    null,
    null,
    null,
    null,
    null,
    null,
    null
  ]
}

What happened in this session:

06:48:12 - Pre-session equipment requirement notification
07:00:00 - Pit lane opens (GREEN), session can begin
09:11:03 - YELLOW flag in sector 11 (mini-sector, likely debris or incident)
09:11:25 - RED FLAG - Session stopped due to serious incident
09:13:18 - Track cleared, ready to resume
09:13:20 - Another YELLOW in sector 11 (follow-up inspection)
09:16:01 - Sector 11 CLEAR
09:16:10 - Session will resume at 12:17 (delayed restart)

Message Categories Explained

Flag Messages
DRS Messages
Car Events
Other Messages

Category: "Flag"Flag messages communicate track safety status:

Green Flag

Meaning: Track is clear, racing can begin/resume
Driver action: Full racing speed allowed
Example: {"cat": "Flag", "msg": "GREEN LIGHT - PIT EXIT OPEN", "flag": "GREEN", "scope": "Track"}

Yellow Flag

Meaning: Hazard on track (debris, stopped car, marshal activity)
Driver action: Slow down, no overtaking in affected sector
Scope: Usually sector-specific (1-24 mini-sectors)
Example: {"cat": "Flag", "msg": "YELLOW IN TRACK SECTOR 11", "flag": "YELLOW", "scope": "Sector", "sector": 11}

Red Flag

Meaning: Session stopped, unsafe to continue
Driver action: Return to pit lane immediately
Reasons: Major accident, barrier damage, severe weather
Example: {"cat": "Flag", "msg": "RED FLAG - RACE SUSPENDED", "flag": "RED", "scope": "Track"}

Chequered Flag

Meaning: Session ended
Driver action: Complete current lap and return to pits
Example: {"cat": "Flag", "msg": "CHEQUERED FLAG", "flag": "CHEQUERED", "scope": "Track"}

Clear

Meaning: Previous flag condition resolved
Driver action: Resume normal racing
Example: {"cat": "Flag", "msg": "CLEAR IN TRACK SECTOR 11", "flag": "CLEAR", "scope": "Sector", "sector": 11}

Category: "Drs"DRS (Drag Reduction System) status messages:

DRS Enabled

Meaning: Drivers can use DRS in designated zones
Conditions: Usually enabled after lap 2 in races, immediately in practice/qualifying
Example: {"cat": "Drs", "msg": "DRS ENABLED", "status": "ENABLED", "scope": "Track"}

DRS Disabled

Meaning: DRS usage not allowed
Reasons: Yellow flags, wet conditions, safety car, race start
Example: {"cat": "Drs", "msg": "DRS DISABLED", "status": "DISABLED", "scope": "Track"}

DRS is automatically disabled under yellow flag conditions and during safety car periods. It is re-enabled once track conditions are clear.

Category: "CarEvent"Driver-specific incidents and penalties:

Unsafe Release

Meaning: Driver released from pit stop into path of another car
Penalty: Typically time penalty or fine
Example: {"cat": "CarEvent", "msg": "CAR 44 - UNSAFE RELEASE", "scope": "Driver", "dNum": "44"}

Track Limits

Meaning: Driver exceeded track limits (all 4 wheels off track)
Consequence: Lap time deleted, warning, or penalty
Example: {"cat": "CarEvent", "msg": "CAR 16 - TRACK LIMITS TURN 4", "scope": "Driver", "dNum": "16"}

Penalties

Types: Time penalties (5s, 10s), drive-through, stop-go, grid penalties
Example: {"cat": "CarEvent", "msg": "CAR 1 - 5 SECOND TIME PENALTY", "scope": "Driver", "dNum": "1"}

Category: "Other"General session information and administrative messages:

Session start/end times
Equipment requirements
Pit lane status
Overtake mode status
Track condition updates

Examples:

{"cat": "Other", "msg": "SESSION WILL START AT 14:00", "scope": "Track"}
{"cat": "Other", "msg": "OVERTAKE ENABLED", "status": "ENABLED", "scope": "Track"}
{"cat": "Other", "msg": "STRAIGHT MODE - LOW GRIP", "scope": "Track"}

Track Status Codes

Race control messages correlate with track status codes found in the Lap Times status field:

Code	Status	Corresponding Message	Impact
`1`	Track Clear	”TRACK CLEAR”, “CLEAR IN SECTOR X”	Normal racing
`2`	Yellow Flag	”YELLOW IN TRACK SECTOR X”	No overtaking, reduced speed
`3`	Unknown/Unused	Rarely observed	System reserved
`4`	Safety Car	”SAFETY CAR DEPLOYED”	All cars bunch up
`5`	Red Flag	”RED FLAG - RACE SUSPENDED”	Session stopped
`6`	VSC Deployed	”VIRTUAL SAFETY CAR”	Controlled speed delta
`7`	VSC Ending	”VIRTUAL SAFETY CAR ENDING”	Prepare for restart

Use Cases

Strategic Analysis

Pit Window Optimization

# Identify safety car periods (opportunity for "free" pit stops)
safety_car_periods = [
    msg for msg in rcm_data 
    if msg['cat'] == 'Flag' and 'SAFETY CAR' in msg['msg']
]

# Correlate with pit stop timing from lap times data
# Teams that pit during SC lose less time

Yellow Flag Impact

# Find yellow flag periods and affected sectors
yellow_flags = [
    (msg['time'], msg['sector']) 
    for msg in rcm_data 
    if msg['flag'] == 'YELLOW'
]

# Cross-reference with lap times to measure lap time loss
# in affected sectors during yellow flag periods

Race Reconstruction

Timeline Visualization

Plot message timestamps on a timeline
Color-code by category (flags, DRS, car events)
Overlay with lap times to show impact on pace
Identify chaotic periods with multiple incidents

Incident Analysis

Filter for RED FLAG messages to identify major incidents
Look at preceding YELLOW flags to trace incident development
Correlate with telemetry data to understand what happened

Penalty Tracking

Driver Penalties

# Extract all car event messages
car_events = [msg for msg in rcm_data if msg['cat'] == 'CarEvent']

# Group by driver number
from collections import defaultdict
penalties_by_driver = defaultdict(list)

for event in car_events:
    if event['dNum']:
        penalties_by_driver[event['dNum']].append(event['msg'])

# Identify drivers with most infractions

DRS Zone Analysis

DRS Availability Timeline

Track when DRS is enabled/disabled throughout session
Correlate with yellow flags (DRS auto-disables)
Measure overtaking success rate during DRS-enabled periods
Compare with Telemetry DRS usage data

Data Quality Notes

Race control messages are timestamped with wall-clock time (ISO 8601), not session time. To correlate with lap times or telemetry (which use session time), you’ll need to calculate the session start time and convert accordingly.

Some messages may be issued retroactively or updated. The message stream represents the official record as finalized after the session.

Mini-Sector Reference

The track is divided into 24 mini-sectors (3 main sectors × 8 mini-sectors each):

Main Sector	Mini-Sectors	Description
Sector 1	1-8	First third of track
Sector 2	9-16	Middle third of track
Sector 3	17-24	Final third of track

Example: “YELLOW IN TRACK SECTOR 11” refers to mini-sector 11, which is the 3rd mini-sector of Sector 2.

Lap Times - Track status codes and lap timing impact
Weather - Weather conditions triggering red flags or wet flags
Telemetry - Detailed driver response to flags and incidents
Drivers - Driver information for penalty tracking

Core Data Types

Field Specifications

Overview

File Location

Data Structure

Field Reference

Core Message Information

Flag Information

Scope and Location

Real Data Example

Message Categories Explained

Green Flag

Yellow Flag

Red Flag

Chequered Flag

Clear

DRS Enabled

DRS Disabled

Unsafe Release

Track Limits

Penalties

Track Status Codes

Use Cases

Strategic Analysis

Race Reconstruction

Penalty Tracking

DRS Zone Analysis

Data Quality Notes

Mini-Sector Reference

Build docs developers (and LLMs) love

Core Data Types

Field Specifications

​Overview

​File Location

​Data Structure

​Field Reference

​Core Message Information

​Flag Information

​Scope and Location

​Real Data Example

​Message Categories Explained

​Green Flag

​Yellow Flag

​Red Flag

​Chequered Flag

​Clear

​DRS Enabled

​DRS Disabled

​Unsafe Release

​Track Limits

​Penalties

​Track Status Codes

​Use Cases

​Strategic Analysis

​Race Reconstruction

​Penalty Tracking

​DRS Zone Analysis

​Data Quality Notes

​Mini-Sector Reference

​Related Pages

Build docs developers (and LLMs) love

Overview

File Location

Data Structure

Field Reference

Core Message Information

Flag Information

Scope and Location

Real Data Example

Message Categories Explained

Green Flag

Yellow Flag

Red Flag

Chequered Flag

Clear

DRS Enabled

DRS Disabled

Unsafe Release

Track Limits

Penalties

Track Status Codes

Use Cases

Strategic Analysis

Race Reconstruction

Penalty Tracking

DRS Zone Analysis

Data Quality Notes

Mini-Sector Reference

Related Pages