Street Exercises: Speed Sensing

Published: November 30, 2015

One of the more difficult skills to both acquire and teach is speed sensing, which is having an idea of how fast the vehicle is moving at the present moment. Speed sensing is important for estimating braking points at a new track or during warm-up laps in the first session of an event as well as for judging whether the car is too traveling too fast when it is approaching a corner on a full out lap and hence corrective action would shortly be required. How can speed sensing skill be improved?

Gear Selection

An easy way to practice speed sensing is gear selection during braking or passing. When braking for a light that turns green for example, which gear do you downshift to? The goal is to have a particular RPM range in mind and pick the gear which results in the engine being in that range.

For example, when I drive my truck I upshift into second gear at 10 mph, third gear at 15 mph and fourth gear at 20 mph. Hence when I am cruising at 30 mph and coming to a red light that turns green, if I decelerated to 20-25 mph before the light turned I would downshift from 5th to 4th, if I decelerated to 15-20 mph I would downshift to 3rd, and so on.

Downshifting for passing works the same way except the target RPM range is higher.

Braking

Generally people start braking way early in street driving. The most glaring example of this is on highway off-ramps - these ramps are designed to provide space for deceleration, yet many drivers brake in the travel lanes before they get to the exit lanes to the point of impeding through traffic. A typical driver can cut their braking distances in half without looking like they are a nutcase.

The speed sensing exercise here is to brake later such as to reduce or eliminate coasting between initial brake application and the eventual stop (or, if not coming to a stop, eventual acceleration).

Tagged: intermediate