Connecticut DUI law falls under Section 14-227a of the general statutes (operation while under the influence of liquor or drug or while having an elevated blood alcohol content). It is as follows.

(a) Operation while under the influence or while having an elevated blood alcohol content. No person shall operate a motor vehicle while under the influence of intoxicating liquor or any drug or both. A person commits the offense of operating a motor vehicle while under the influence of intoxicating liquor or any drug or both if such person operates a motor vehicle on a public highway of this state or on any road of a district organized under the provisions of chapter 105, a purpose of which is the construction and maintenance of roads and sidewalks, or on any private road on which a speed limit has been established in accordance with the provisions of section 14-218a, or in any parking area for ten or more cars or on any school property (1) while under the influence of intoxicating liquor or any drug or both, or (2) while such person has an elevated blood alcohol content. For the purposes of this section, “elevated blood alcohol content” means a ratio of alcohol in the blood of such person that is eight-hundredths of one per cent or more of alcohol, by weight.

(b) Admissibility of chemical analysis. Except as provided in subsection (c) of this section, in any criminal prosecution for violation of subsection (a) of this section, evidence respecting the amount of alcohol or drug in the defendant’s blood or urine at the time of the alleged offense, as shown by a chemical analysis of the defendant’s breath, blood or urine shall be admissible and competent provided: (1) The defendant was afforded a reasonable opportunity to telephone an attorney prior to the performance of the test and consented to the taking of the test upon which such analysis is made; (2) a true copy of the report of the test result was mailed to or personally delivered to the defendant within twenty-four hours or by the end of the next regular business day, after such result was known, whichever is later; (3) the test was performed by or at the direction of a police officer according to methods and with equipment approved by the Department of Public Safety and was performed in accordance with the regulations adopted under subsection (d) of this section; (4) the device used for such test was checked for accuracy in accordance with the regulations adopted under subsection (d) of this section; (5) an additional chemical test of the same type was performed at least thirty minutes after the initial test was performed or, if requested by the police officer for reasonable cause, an additional chemical test of a different type was performed to detect the presence of a drug or drugs other than or in addition to alcohol, provided the results of the initial test shall not be inadmissible under this subsection if reasonable efforts were made to have such additional test performed in accordance with the conditions set forth in this subsection and such additional test was not performed or was not performed within a reasonable time, or the results of such additional test are not admissible for failure to meet a condition set forth in this subsection; and (6) evidence is presented that the test was commenced within two hours of operation. In any prosecution under this section it shall be a rebuttable presumption that the results of such chemical analysis establish the ratio of alcohol in the blood of the defendant at the time of the alleged offense, except that if the results of the additional test indicate that the ratio of alcohol in the blood of such defendant is twelve-hundredths of one per cent or less of alcohol, by weight, and is higher than the results of the first test, evidence shall be presented that demonstrates that the test results and the analysis thereof accurately indicate the blood alcohol content at the time of the alleged offense.

(c) Evidence of blood alcohol content. In any prosecution for a violation of subdivision (1) of subsection (a) of this section, reliable evidence respecting the amount of alcohol in the defendant’s blood or urine at the time of the alleged offense, as shown by a chemical analysis of the defendant’s blood, breath or urine, otherwise admissible under subsection (b) of this section, shall be admissible only at the request of the defendant.

(d) Testing and analysis of blood, breath and urine. The Commissioner of Public Safety shall ascertain the reliability of each method and type of device offered for chemical testing and analysis purposes of blood, of breath and of urine and certify those methods and types which said commissioner finds suitable for use in testing and analysis of blood, breath and urine, respectively, in this state. The Commissioner of Public Safety shall adopt regulations, in accordance with chapter 54, governing the conduct of chemical tests, the operation and use of chemical test devices, the training and certification of operators of such devices and the drawing or obtaining of blood, breath or urine samples as said commissioner finds necessary to protect the health and safety of persons who submit to chemical tests and to insure reasonable accuracy in testing results. Such regulations shall not require re-certification of a police officer solely because such officer terminates such officer’s employment with the law enforcement agency for which certification was originally issued and commences employment with another such agency.

(e) Evidence of refusal to submit to test. In any criminal prosecution for a violation of subsection (a) of this section, evidence that the defendant refused to submit to a blood, breath or urine test requested in accordance with section 14-227b shall be admissible provided the requirements of subsection (b) of said section have been satisfied. If a case involving a violation of subsection (a) of this section is tried to a jury, the court shall instruct the jury as to any inference that may or may not be drawn from the defendant’s refusal to submit to a blood, breath or urine test.

(f) Reduction, nolle or dismissal prohibited. If a person is charged with a violation of the provisions of subsection (a) of this section, the charge may not be reduced, nolled or dismissed unless the prosecuting authority states in open court such prosecutor’s reasons for the reduction, nolle or dismissal.

(g) Penalties for operation while under the influence. Any person who violates any provision of subsection (a) of this section shall: (1) For conviction of a first violation, (A) be fined not less than five hundred dollars or more than one thousand dollars, and (B) be (i) imprisoned not more than six months, forty-eight consecutive hours of which may not be suspended or reduced in any manner, or (ii) imprisoned not more than six months, with the execution of such sentence of imprisonment suspended entirely and a period of probation imposed requiring as a condition of such probation that such person perform one hundred hours of community service, as defined in section 14-227e, and (C) have such person’s motor vehicle operator’s license or nonresident operating privilege suspended for one year; (2) for conviction of a second violation within ten years after a prior conviction for the same offense, (A) be fined not less than one thousand dollars or more than four thousand dollars, (B) be imprisoned not more than two years, one hundred twenty consecutive days of which may not be suspended or reduced in any manner, and sentenced to a period of probation requiring as a condition of such probation that such person perform one hundred hours of community service, as defined in section 14-227e, and (C) (i) have such person’s motor vehicle operator’s license or nonresident operating privilege suspended for three years or until the date of such person’s twenty-first birthday, whichever is longer, or (ii) if such person has been convicted of a violation of subdivision (1) of subsection (a) of this section on account of being under the influence of intoxicating liquor or of subdivision (2) of subsection (a) of this section, have such person’s motor vehicle operator’s license or nonresident operating privilege suspended for one year and be prohibited for the two-year period following completion of such period of suspension from operating a motor vehicle unless such motor vehicle is equipped with a functioning, approved ignition interlock device, as defined in section 14-227j; and (3) for conviction of a third and subsequent violation within ten years after a prior conviction for the same offense, (A) be fined not less than two thousand dollars or more than eight thousand dollars, (B) be imprisoned not more than three years, one year of which may not be suspended or reduced in any manner, and sentenced to a period of probation requiring as a condition of such probation that such person perform one hundred hours of community service, as defined in section 14-227e, and (C) have such person’s motor vehicle operator’s license or nonresident operating privilege permanently revoked upon such third offense. For purposes of the imposition of penalties for a second or third and subsequent offense pursuant to this subsection, a conviction under the provisions of subsection (a) of this section in effect on October 1, 1981, or as amended thereafter, a conviction under the provisions of either subdivision (1) or (2) of subsection (a) of this section, a conviction under the provisions of section 53a-56b or 53a-60d or a conviction in any other state of any offense the essential elements of which are determined by the court to be substantially the same as subdivision (1) or (2) of subsection (a) of this section or section 53a-56b or 53a-60d, shall constitute a prior conviction for the same offense.