I was driving to work this morning when this question occurred to me. I was going up a clover-leaf entrance ramp to the highway. The person in front of me was lazily floating the outside of the curve, whereas I always tend to hug the inside of the curve. Hugging the inside of the curve tends to lead to an apparently higher speed... and I soon had to apply the brakes to avoid hitting the floater in front of me.

This made me wonder, why does hugging the inside of the turn yield an apparently faster speed?

  1. Is it simply because the inside is a shorter radius and thus you traverse it more quickly, thereby appearing to go faster (something I know track racers take advantage of, thus the expression "he's got the inside track")?

  2. Or, it occurred to me that it could be similar to the way a figure skater performing a pirouette speeds up as she pulls her arms and legs inwards. So as you continually pull your car inwards on the curve it actually does increase its velocity.

Does the second concept actually come into play here, yielding an actual faster velocity? Or is it simply the first concept, yielding only an apparent faster velocity?

(assuming our cars are identical weight, engine power, etc.)


1 Answer 1


If you're both going at a constant speed, lets say 35 MPH, then it would appear so.

This is because the distance is shorter in the inner arc in which you are traveling compared to the outer arc in which the other vehicle is traveling.

  • 1
    $\begingroup$ That makes sense. When would the second come into play? I'm wondering, would that apply if rather than saying we are both going the same speed, it is stated we are both applying the same acceleration? $\endgroup$
    – eidylon
    May 11, 2015 at 18:27
  • $\begingroup$ A car in a turn will tend to stay within that turn, physically speaking, but will require thrust (gas) to continue at that velocity. Staying in that turn will slow the car down. Pulling into the turn will cause it to speed up, yes. $\endgroup$
    – Rincewind
    May 11, 2015 at 18:32

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