NASCAR Chaos Index

Measuring race unpredictability from 0-100

Not all NASCAR races are created equal. Some follow the script: the fastest car leads from flag to flag and the favorites finish where you'd expect. Others descend into beautiful chaos: big wrecks, underdog winners, lead changes every few laps, and results that no model could have predicted. The Chaos Index quantifies that unpredictability.

Every Cup Series race from 1949 to the present receives a 0-100 score based on four components: how much the running order shuffled, whether underdogs crashed the top 5, how many favorites dropped out, and how many different drivers led laps. Superspeedways like Daytona and Talladega tend to score highest, but road courses and weather-affected races can surprise you.

100.0
Most Chaotic Race
13.5
Calmest Track Avg
99.5
Top 50 Avg Score
How the Chaos Index Works

The Chaos Index scores every NASCAR Cup Series race on a 0-100 scale measuring unpredictability. Each score combines four equally-weighted components (0-25 points each), computed from our race results database covering every season from 1949 to the present.

Position Churn: how much the field shuffled Upset Factor: underdogs in the top 5 Attrition: favorites dropping out Leader Diversity: many different leaders
0-25 Calm 26-50 Moderate 51-75 Chaotic 76-100 Wild

Most Chaotic Races (Top 50)

The 50 highest-scoring Cup Series races by Chaos Index. These are the events where anything that could go wrong did go wrong, or right, depending on your perspective. Click any race to see the full results and relive the madness.

Rank Race Season Track Score
1 Coke Zero Sugar 400 2024 Daytona International Speedway 100.0
2 Daytona 500 2023 Daytona International Speedway 100.0
3 Goodyear 400 2022 Darlington Raceway 100.0
4 Coke Zero Sugar 400 2022 Daytona International Speedway 100.0
5 Daytona 500 2021 Daytona International Speedway 100.0
6 Coke Zero Sugar 400 2018 Daytona International Speedway 100.0
7 Coke Zero 400 2017 Daytona International Speedway 100.0
8 Alabama 500 2017 Talladega Superspeedway 100.0
9 Daytona 500 2001 Daytona International Speedway 100.0
10 Transouth Financial 400 1995 Darlington Raceway 100.0
11 Mountain Dew Southern 500 1994 Darlington Raceway 100.0
12 Mello Yello 500 1994 Charlotte Motor Speedway 100.0
13 Budweiser 500 1993 Dover International Speedway 100.0
14 Hooters 500 1993 Atlanta Motor Speedway 100.0
15 Motorcraft 500 1989 Atlanta Motor Speedway 100.0
16 TranSouth 500 1987 Darlington Raceway 100.0
17 Coca-Cola 600 1987 Charlotte Motor Speedway 100.0
18 Oakwood 500 1987 Charlotte Motor Speedway 100.0
19 Daytona 500 1986 Daytona International Speedway 100.0
20 Summer 500 1985 Pocono Raceway 100.0
21 Talladega 500 1985 Talladega Superspeedway 100.0
22 Winston 500 1983 Talladega Superspeedway 100.0
23 National 500 1981 Charlotte Motor Speedway 100.0
24 Atlanta Journal 500 1981 Atlanta Motor Speedway 100.0
25 Atlanta 500 1980 Atlanta Motor Speedway 100.0
26 Daytona 500 1976 Daytona International Speedway 100.0
27 Winston 500 1975 Talladega Superspeedway 100.0
28 Daytona 500 1974 Daytona International Speedway 100.0
29 Winston 500 1974 Talladega Superspeedway 100.0
30 Southern 500 1974 Darlington Raceway 100.0
31 Winston 500 1973 Talladega Superspeedway 100.0
32 Talladega 500 1973 Talladega Superspeedway 100.0
33 Peach Blossom 500 1966 Rockingham Speedway 100.0
34 Talladega 500 1983 Talladega Superspeedway 99.7
35 YellaWood 500 2024 Talladega Superspeedway 99.0
36 Daytona 500 2020 Daytona International Speedway 99.0
37 YellaWood 500 2020 Talladega Superspeedway 99.0
38 1000Bulbs.com 500 2019 Talladega Superspeedway 99.0
39 Daytona 500 2017 Daytona International Speedway 99.0
40 Daytona 500 2013 Daytona International Speedway 99.0
41 Daytona 500 2011 Daytona International Speedway 99.0
42 Mello Yello 500 1990 Charlotte Motor Speedway 99.0
43 Daytona 500 1970 Daytona International Speedway 99.0
44 Coca-Cola 600 1989 Charlotte Motor Speedway 98.0
45 Daytona 500 2019 Daytona International Speedway 97.5
46 Diehard 500 1995 Talladega Superspeedway 97.5
47 Southern 500 1985 Darlington Raceway 97.5
48 Southern 500 1984 Darlington Raceway 97.5
49 Warner W. Hodgdon Carolina 500 1982 Rockingham Speedway 97.5
50 Coca-Cola 500 1981 Atlanta Motor Speedway 97.5

Most Chaotic Tracks

Top 15 tracks by average Chaos Index score across all Cup Series races. Some venues are simply built for chaos: tight quarters, high speeds, or unpredictable weather create conditions where the unexpected becomes routine.

Rank Track Avg Score
1 Michigan State Fairgrounds 87.5
2 EchoPark Speedway 86.2
3 Star Lite Speedway 83.6
4 San Diego Street Course 82.9
5 Talladega Superspeedway 82.4
6 Lowe's Motor Speedway 79.2
7 Autodromo Hermanos Rodriguez 78.0
8 California Speedway 76.8
9 Charlotte Motor Speedway 75.3
10 Atlanta Motor Speedway 75.0
11 Chicago Street Course 74.0
12 Daytona International Speedway 73.8
13 North Carolina Speedway 73.2
14 Indianapolis Motor Speedway 73.1
15 Darlington Raceway 72.5

Most Chaotic Seasons

Top 15 seasons by average Chaos Index score across all Cup races that year. Rule changes, new car packages, and parity shifts all affect how chaotic a season feels; some years are pure survival mode from Daytona to Homestead.

Rank Season Avg Score
1
1994 77.8
2
2002 76.3
3
2007 76.1
4
1987 76.0
5
2003 75.8
6
2001 75.7
7
1988 75.6
8
1996 74.8
9
1993 74.7
10
1982 74.3
11
2004 74.2
12
1995 74.2
13
2006 73.7
14
1997 73.6
15
1999 73.2

Frequently Asked Questions

What is the NASCAR Chaos Index?
The Chaos Index is a 0-100 score measuring race unpredictability. It combines four equally-weighted components: Position Churn (how much the field shuffled from start to finish), Upset Factor (underdogs reaching the top 5), Attrition (favorites dropping out early), and Leader Diversity (how many different drivers led laps).
What makes a race chaotic?
Races score highest when favorites drop out due to crashes or mechanical failures, underdogs reach the top 5, positions shuffle dramatically between the start and the finish, and many different drivers lead laps throughout the event.
Which NASCAR track is the most chaotic?
Michigan State Fairgrounds leads all tracks with an average Chaos Index of 87.5 across all Cup Series races held there. See the Most Chaotic Tracks table below for the full top 15.
Do superspeedway races have higher chaos scores?
Generally yes. Superspeedways like Daytona and Talladega tend to produce higher chaos scores due to pack racing, frequent multi-car crashes, and dramatic position swings. However, road courses also score high thanks to significant position churn between start and finish.
How far back does the Chaos Index go?
We compute Chaos Index scores for all NASCAR Cup Series races from 1949 to the present. Pre-1995 scores may rely on fewer data points (some lack start position or laps led data), so those races receive neutral mid-range values for missing components.

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