The Real Math

Even in pure theoretical terms, without any traffic at all, the gains are smaller than most people assume. Going 10 km/h over the limit on a typical commute-length drive saves only a few minutes — and the higher the speed limit already is, the less time an extra 10 km/h actually buys you, since the relationship between speed and time isn’t a straight line. Add real-world traffic lights and congestion, and most of that theoretical gain evaporates before you even reach the next intersection.

Why Tailgating Doesn’t Help Either

Following closely feels like it should get you through traffic faster, but it doesn’t change your average speed at all. Also see our guide on distracted driving — another habit that feels low-risk until it isn’t. All it actually does is remove your margin for reacting if the car ahead brakes suddenly, while the car ahead’s speed (not your following distance) is what actually determines how fast the whole line of traffic moves.

The Actual Cost of Closing the Gap

• Crash risk rises sharply with speed, not gradually — a small increase in speed disproportionately increases both the chance of a collision and its severity.
• Fuel economy drops fast at higher speeds — driving meaningfully over the limit can cut fuel efficiency by 15–20%, which adds up to real money over a year of driving.
• A conviction costs far more than the minutes saved — see our guide to demerit points and insurance consequences for what a single ticket can actually cost you over the following years.

The 3-Second Rule, and Why It Works

Pick a fixed point — a sign, a shadow, an overpass — and count the seconds between the car ahead passing it and you reaching the same spot. Three seconds in good conditions (more in rain, snow, or fog) gives you enough time to actually process a hazard and react, rather than just react on reflex. It costs you nothing in travel time, since you’re moving at the same average speed as the traffic around you either way — it only changes how much margin you have if something goes wrong.

A Mental Habit Worth Building

Next time the urge to close a gap or push the speed shows up, it’s worth doing the actual math in your head for ten seconds: how much time is this realistically buying me over the rest of this drive? For almost every real trip, the honest answer is somewhere between “none” and “under a minute” — and that’s before counting the risk, the fuel cost, or what a ticket would actually cost over the next few years.

The Bottom Line

The math isn’t close: closing the gap, whether by speeding or tailgating, buys you seconds to at most a couple of minutes on almost any real drive, while meaningfully raising your risk, your fuel cost, and your exposure to a conviction that follows you for years. Keeping your distance and driving the limit isn’t a compromise — it’s very close to the same trip, with a real safety margin attached for free.