In automotive performance terms, a "40 roll" refers to a type of unsanctioned race where two vehicles accelerate side-by-side from a rolling start of 40 miles per hour. Unlike a "dig" race that starts from a complete stop, a roll race begins with both cars already moving at a set speed. This format is popular for testing a car's powerband and acceleration in a real-world highway scenario, focusing on mid-range torque and transmission response rather than just launch control.
The appeal of a 40 roll lies in its accessibility and relative safety compared to stoplight racing. It minimizes stress on drivetrain components like the clutch and axles that can occur during a hard launch. For modern high-horsepower cars, especially those with all-wheel drive or sophisticated traction control, a 40-mph punch is often where they can put power down most effectively. Racers typically use a three-beep countdown over a communication device to synchronize the start before stomping on the throttle.
Performance outcomes vary significantly based on the car's modifications. A vehicle with a large turbocharger might experience "turbo lag" at 40 mph, allowing a naturally aspirated muscle car to jump ahead initially. The race usually ends at a predetermined speed, like 120 or 130 mph. It's crucial to note that such activities are dangerous and illegal on public roads.
| Race Type | Starting Speed | Focuses On | Common Location |
|---|
| 40 Roll | 40 mph | Mid-range power, highway pulls | Highway on-ramps |
| Dig | 0 mph (standing start) | Launch control, traction | Stoplights, drag strips |
| 60 Roll | 60 mph | High-speed acceleration | Open highways |
| Hit | One car rolls, the other "hits" the gas to join | Spontaneous challenge | Any road |
