Car and Driver - USA (2019-12)

TESTING, TESTING, 1, 2, 3

Roll

Reversal

By adopting an industry

standard, we’ve

changed how we report

acceleration.

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ILLUSTRATION BY TAVIS COBURN ~ DECEMBER 2019 ~ CAR AND DRIVER

FACE THE

CLOCK

Here’s how our

change affects the

C8 Corvette on

page 26. The C

accelerates to 3

mph in 0.1 second,

but the one-foot

time is 0.2 second,

at which point the

Corvette is going

6 mph. In general,

acceleration times

for most cars will

improve by about

0.1 second with the

new procedure. In

the interest of full

disclosure, we’ll be

publishing the one-

foot-rollout time

of every tested

vehicle so you

can add it to the

acceleration times

to arrive at true

zero-to-X measure-

ments. We also will

be recalculating

times for past

vehicles, so that

any comparisons

we make today are

apples to apples.

Unfortunately, it

is impossible to

recrunch pre-VBox

test results. We

will generate

estimates in those

rare instances.

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WHAT IS ROLLOUT?
—
Lining up a vehicle at a drag
strip requires careful place-
ment of the front tires relative
to two beams of light. When
a car’s front tire crosses the
first one, a “prestage” warning
is lit. When the tire interrupts

the second beam—the “stage

beam,” which is seven inches

ahead—the car is staged and

ready for a run. The clock

starts when the car’s tire

moves enough to uncover

the second light beam. The

distance the car travels before

the stage beam is uncovered

(and therefore the timing

begins) is what’s known as

rollout, and it can vary from

nothing to more than a foot.

Obviously, this affects the

elapsed time, sometimes by

as much as 0.3 second. Our

testing now adopts the indus-

try-standard one-foot rollout.