Moving to Metric 25 mm by 25 mm (Inch by Inch)
Most highway engineers and contractors have gotten used to working with metric
measurements, prompted in large part by the switch to metric specifications in Federal-aid
construction contracts. Many of the rest of us, however, are still adjusting to the metric
system (officially known as the International System of Units, or SI).
That's why articles in Focus contain both metric units and English (inch-pound)
units. Although including metric and English units in a story can sometimes be a bit
cumbersome, we do so to help familiarize Focus readers with metric equivalents to
common English measurements.
Beginning with this issue of Focus, the metric measurement will always be listed
first, with the English units in parentheses. In time, we will drop the English units
To convert from one system to another, we follow the guidelines in IEEE/ASTM SI-10, Standard
for Use of the International System of Units (SI): The Modern Metric System (which
replaced E380, Standard for Metric Practice). The report is available from the
American Society of Testing and Materials (telephone: 610-832-9585; fax: 610-832-9555).
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