On-field testing is conducted in the test site, safety measures are more in place, some extreme tests, such as crash tests are done in the test site, even if the accident is generally not life-threatening. Off-site tests are conducted on social roads, such as the test of intelligent driving standards, seasonal tests, comprehensive road tests, etc., the risk will be higher.
The test is a measurement with the nature of the test, that is, the combination of measurement and test. And the means of testing is instrumentation. Because test and measurement are closely related, in actual use often does not strictly distinguish between test and measurement.