Driving at 90 instead of 70 felt like a significant time saving. The actual saving, over a thirty-minute journey, was under four minutes.

Time-saving bias is the tendency to misjudge the amount of time saved or lost when changing speed, underestimating savings from low speeds and overestimating savings from high speeds.

A Scene Worth Recognising

A product team reviews the features that made their last three launches successful and sets out to replicate every pattern they find. The review is thorough β€” but it only covers the launches that went well. The four features that appeared in failed launches and were quietly removed do not make it into the analysis. What drives the next roadmap is shaped by Time-saving bias.

What it means and how it works

The bias stems from applying a linear heuristic (Ξ”time β‰ˆ kΒ·Ξ”speed) to a hyperbolic function (time = distance/speed). When the baseline speed is low, the curve is steep, so the linear heuristic underestimates the true time saved; when the baseline speed is high, the curve is flat, causing an overestimation.

People intuitively treat the relationship between speed and travel time as linear, assuming that a given increase in speed yields a constant amount of time saved regardless of the starting speed. In reality, travel time is inversely proportional to speed, so the same absolute increase in speed saves more time when starting from a low speed and less time when starting from a high speed. This mismatch leads to systematic errors in estimating how much time will be gained (or lost) by speeding up or slowing down.

Why it matters

Misestimating time savings can affect travel planning, fuel consumption decisions, and risk-taking behaviors (e.g., unnecessary speeding). It may also influence judgments in domains where speed adjustments are considered, such as manufacturing throughput, data processing, or project scheduling.

The verified research on this pattern supports the following:

  • Individuals tend to misjudge time savings when changing speeds, leading to suboptimal speed decisions.
  • The bias arises because time saved is inversely proportional to speed, producing a nonlinear relationship that people interpret linearly.
  • Individuals consistently underestimate time saved when increasing speed from a low baseline (e.g., 30 to 40 km/h) and overestimate time saved when increasing speed from a high baseline (e.g., 80 to 90 km/h).

Common misunderstandings

Misunderstanding 1: That the bias only leads to overestimation of time savings.

Misunderstanding 2: That it applies equally to all types of tasks, ignoring that the effect is strongest when distance is fixed and speed is the variable.

Misunderstanding 3: That awareness of the bias eliminates the error; in practice, people still rely on intuition despite knowing the correct formula.

Sources

  • Niroula, Rishab. REV 2.0 Topic Catalog. Hello to Halo.
  • Svenson, Ola. "Differentiation and Consolidation Theory of Human Decision Making." Acta Psychologica 80, no. 1–3 (1992): 143–168.
  • Kahneman, Daniel. Thinking, Fast and Slow. Farrar, Straus and Giroux, 2011.

The next time this pattern surfaces, the move is not to fight it β€” it is to notice it. Naming Time-saving bias creates a moment of pause before the decision. That moment is usually enough.