# Synthesis of Variable Speed Limit Signs

## SI* (Modern Metric) Conversion Factors

APPROXIMATE CONVERSIONS TO SI UNITS |

SYMBOL |
WHEN YOU KNOW |
MULTIPLY BY |
TO FIND |
SYMBOL |

LENGTH |

in |
inches |
25.4 |
millimeters |
mm |

ft |
feet |
0.305 |
meters |
m |

yd |
yards |
0.914 |
meters |
m |

mi |
miles |
1.61 |
kilometers |
km |

AREA |

in^{2} |
square inches |
645.2 |
square millimeters |
mm^{2} |

ft^{2} |
square feet |
0.093 |
square meters |
m^{2} |

yd^{2} |
square yard |
0.836 |
square meters |
m^{2} |

ac |
acres |
0.405 |
hectares |
ha |

mi^{2} |
square miles |
2.59 |
square kilometers |
km^{2} |

VOLUME |

fl oz |
fluid ounces |
29.57 |
milliliters |
mL |

gal |
gallons |
3.785 |
liters |
L |

ft^{3} |
cubic feet |
0.028 |
cubic meters |
m^{3} |

yd^{3} |
cubic yards |
0.765 |
cubic meters |
m^{3} |

NOTE: volumes greater than 1000 L shall
be shown in m^{3} |

MASS |

oz |
ounces |
28.35 |
grams |
g |

lb |
pounds |
0.454 |
kilograms |
kg |

T |
short tons (2000 lb) |
0.907 |
megagrams (or "metric ton") |
Mg (or "t") |

TEMPERATURE (exact degrees) |

^{o}F |
Fahrenheit |
5 (F-32)/9
or (F-32)/1.8 |
Celsius |
^{o}C |

ILLUMINATION |

fc |
foot-candles |
10.76 |
lux |
lx |

fl |
foot-Lamberts |
3.426 |
candela/m^{2} |
cd/m^{2} |

FORCE and PRESSURE or STRESS |

lbf |
poundforce |
4.45 |
newtons |
N |

lbf/in^{2} |
poundforce per square inch |
6.89 |
kilopascals |
kPa |

APPROXIMATE CONVERSIONS FROM SI UNITS |

SYMBOL |
WHEN YOU KNOW |
MULTIPLY BY |
TO FIND |
SYMBOL |

LENGTH |

mm |
millimeters |
0.039 |
inches |
in |

m |
meters |
3.28 |
feet |
ft |

m |
meters |
1.09 |
yards |
yd |

km |
kilometers |
0.621 |
miles |
mi |

AREA |

mm^{2} |
square millimeters |
0.0016 |
square inches |
in^{2} |

m^{2} |
square meters |
10.764 |
square feet |
ft^{2} |

m^{2} |
square meters |
1.195 |
square yards |
yd^{2} |

ha |
hectares |
2.47 |
acres |
ac |

km^{2} |
square kilometers |
0.386 |
square miles |
mi^{2} |

VOLUME |

mL |
milliliters |
0.034 |
fluid ounces |
fl oz |

L |
liters |
0.264 |
gallons |
gal |

m^{3} |
cubic meters |
35.314 |
cubic feet |
ft^{3} |

m^{3} |
cubic meters |
1.307 |
cubic yards |
yd^{3} |

MASS |

g |
grams |
0.035 |
ounces |
oz |

kg |
kilograms |
2.202 |
pounds |
lb |

Mg (or "t") |
megagrams (or "metric ton") |
1.103 |
short tons (2000 lb) |
T |

TEMPERATURE (exact degrees) |

^{o}C |
Celsius |
1.8C+32 |
Fahrenheit |
^{o}F |

ILLUMINATION |

lx |
lux |
0.0929 |
foot-candles |
fc |

cd/m^{2} |
candela/m^{2} |
0.2919 |
foot-Lamberts |
fl |

FORCE and PRESSURE or STRESS |

N |
newtons |
0.225 |
poundforce |
lbf |

kPa |
kilopascals |
0.145 |
poundforce per square inch |
lbf/in^{2} |

*SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380.

(Revised March 2003)