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Daylight

To be ahead of a competitor by more than a car length in side-by-side racing, so daylight is visible between the two vehicles.

Daytime Running Lights

Front and rear lights that remain lit whenever a vehicle's engine is running. They do not provide illumination to drive by, but rather help other drivers spot the vehicle as it is moving down the road. Many automakers are installing daytime running lights for improved safety, but these lights also can be installed after a vehicle has been purchased. Abbreviated DRLs.

Daytona

The Daytona International Speedway.

Daytona International Speedway

A speedway in Daytona Beach, Florida. Home of the Daytona 500, Firecracker 400, and IMSA"s 24-hour sport-car endurance race.

DB

Decibel.

Db

Abbreviation for decibel.

DBC

An acronym for dual-bed catalytic.

DC

An acronym for direct current.

DC Coupling

An oscilloscope setting that allows the scope to display both AC and DC Signals.

DCL

Data communications link.

DCS

Deceleration control system.

DCTO

Dual coolant temperature override.

DDA

Detroit Diesel Allison.

DDC

Diesel Data Center.

DDD

Dual diaphragm distributor.

DDE

European Digital Diesel Electronics.

DDM

Acranym for Drivers Door Module (Chrysler AKA MUX Module).

De Dion Axle

A drive system with a differential or transaxle attached to the frame and exposed, universal-jointed half-shafts driving the wheels with a separate dead axle connecting the wheels that holds them upright and supports the springs.

De Energized

Having the electric current or energy source turned off.

De-arched Leaf Spring

A leaf spring that has a reduced curve. De-arched leaf springs sometimes are used in lowering kits, since they help a vehicle sit lower to the ground. De-arched leaf springs will provide a softer ride than the units they replace, and they also will reduce a vehicle's load-carrying and towing capacity