A person who is operating, attempting to operate, or in actual physical control of a commercial motor vehicle with any measurable or detectable amount of alcohol in his or her system shall immediately be placed out-of-service for 24 hours by an enforcement officer. A law enforcement officer who has reasonable grounds to believe that a person has a measurable or detectable amount of alcohol in his or her system on the basis of the person's general appearance, conduct, or other substantiating evidence, may request the person to submit to a test, which may be administered with a preliminary screening device. The law enforcement officer shall inform the person at the time the test is requested that refusal to submit will result in disqualification. If the person refuses to submit to the test, the person shall immediately be placed out-of-service for 24 hours and shall be disqualified from driving a commercial motor vehicle as provided in section 4116 of this title. (Added 1991, No. 88, § 14.)