An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
To promote uniformity in national and international legal metrology laws, regulations, standards, test procedures, and enforcement practices so as to ensure traceability of measurements to the SI and to enhance consumer protection, foster fair competition, and facilitate economic growth and trade.
To calculate fares, app-based ride services such as Lyft and Uber don’t use traditional taxi meters, but instead combine data from GPS and cellular networks to