S.07 / Safety feature · Grip · Slip control

TRACTION CONTROL

Stops a driven wheel spinning by cutting power or braking it — the foundation of every modern stability and launch-control system.

TRACTION CONTROL — reference photo
Origins
Inventor
Buick (mechanical MaxTrac, 1971); Bosch + Mercedes-Benz (electronic ASR, 1987)
First used
1971 — Buick Riviera with MaxTrac (vacuum-actuated throttle cut); 1987 — Mercedes-Benz W126 S-Class with Bosch ASR
Origin
Detroit, USA (concept) and Stuttgart, Germany (modern electronic system)
History

How it came to be

GM's MaxTrac (1971) was the first production system to recognize wheel spin and intervene — a primitive setup that simply cut ignition timing. It was expensive, unreliable and dropped after a few years. The modern story begins in 1987, when Bosch developed Anti-Slip Regulation (ASR) as a software extension of ABS: the same wheel-speed sensors that detected lockup could detect wheelspin. Mercedes-Benz launched it on the S-Class that year, BMW followed with ASC on the 7-Series in 1988, and within a decade traction control was standard on most premium cars. It later became the building block for ESC (1995), launch control (2002 BMW M3) and EV-specific traction strategies that respond in single-digit milliseconds.

Timeline

Key milestones

  1. 1971
    Buick Riviera launches MaxTrac, the first production traction control.
  2. 1987
    Bosch ASR debuts on the Mercedes-Benz W126 S-Class — the first electronic system.
  3. 1988
    BMW 7-Series adopts ASC; Cadillac follows with Traction Assist.
  4. 1995
    Bosch ESP integrates ASR into a full stability-control package.
  5. 2002
    BMW M3 SMG ships the first production launch control, built on traction-control hardware.
  6. 2012
    TCS becomes mandatory in the US as part of the ESC mandate (FMVSS 126).
  7. 2020
    Porsche Taycan demonstrates 5 ms torque control on each motor — 100× faster than mechanical TCS.
By the numbers
Reaction time (modern electronic TCS)
10–50 ms
Reaction time (EV motor torque control)
≈ 5 ms
Wheel-speed sensors used
4 (same as ABS)
Intervention methods
Throttle cut, spark retard, individual-wheel braking
Regulation

Required wherever ESC is required: all new US passenger vehicles since 2012 (FMVSS 126) and all new EU vehicles since 2014. TCS is the launch case for the broader ESC mandate.

Deep dive
01

Why wheelspin is bad

A spinning tire has dramatically less grip than one rolling at the road's speed. On wet asphalt or snow, a single spinning drive wheel can rob you of acceleration AND of steering control — front-drive cars torque-steer, rear-drive cars step out. Traction control puts the power down where it'll actually move you.

02

How it intervenes

Wheel-speed sensors compare driven-wheel speed to undriven-wheel speed (or vehicle speed from GPS in 4WD cars). If the difference exceeds a threshold, the ECU cuts throttle, retards spark, downshifts, or applies brake to the spinning wheel — usually a combination. On EVs the motor torque is simply commanded down in milliseconds, no brake intervention needed.

03

Launch control

Performance cars repurpose TCS hardware to set the perfect launch RPM, then progressively allow wheelspin as speed builds. Porsche, Ferrari, Nissan GT-R and the Bugatti Chiron use launch control to deliver repeatable 0–60 times within a tenth of a second of each run.

04

Sport mode and off

Track-focused cars (Porsche PSM Sport, Ferrari CT-Off, BMW MDM) raise the slip threshold so the rear can rotate before the system steps in. Fully off is meant for closed circuits. For winter driving, TCS off can occasionally help you rock out of deep snow — but turn it back on the moment the road is clear.

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