[directive] Attorney General Guideline: Page 17  Prosecution of DWI & Refusal Violations  Observation of a Violation, Arrest and Processing of a Defendant  The usual circumstances attendant upon a DWI or DWI refusal arrest include that a law enforcement officer will have observed the operator in the act of operating the vehicle or vessel in a manner suggesting or indicating intoxication or other impairment.  However, circumstances may arise where the observation component may not be possible: e.g., an accident scene, or an encounter at a location where the vehicle or vessel is not moving, but the location is such that operation is inferred (e.g., one car motor vehicle accident, vehicle parked on the side of a limited access roadway, vehicle parked in a rest area, with or without the motor running.)  Once the vehicle has been stopped, the officer will generally continue to observe the operator.  If the officer, based upon their training and experience, suspects the operator is intoxicated or under the influence of alcohol or drugs, then the officer will request the operator to exit the vehicle.  Once the operator is out of the vehicle, the officer will generally request the operator to perform field sobriety tests.  Where possible, the use of uniform field sobriety testing procedures by police officers is preferred.  For those officers with the requisite training, they will generally employ the Standard Field Sobriety Testing [SFST] methods, as taught in the Division of State Police 5-day training course, “Driving While Intoxicated Course/Standardized Field Sobriety Testing [SFST].”  Subject to a limitation, set forth in State v. Doriguzzi, 334 N.J. Super. 530 (App. Div. 2000), Standardized Field Sobriety Testing [SFST] can be used to establish the requisite proofs necessary in an observational prosecution.  The limitation in Doriguzzi, pertains to the use of test.10 only one of the four SFST’s, the Horizontal Gaze Nystagmus [HGN]  State v. Doriguzzi, 334 N.J. Super. at 533.  HGN can, however, be utilized as part of the observations of the police officer which form the totality of circumstances giving rise to the probable cause necessary to arrest the defendant for DWI and to subject the defendant to the provisions of the Implied Consent Statutes.  Upon a determination by the law enforcement officer that there is sufficient probable cause to believe the operator of the vehicle or vessel is intoxicated, under the influence of alcohol or drugs, or has a blood alcohol or alcohol concentration at, or above, the per se limit set by the statute, the officer will place the operator under arrest and advise the operator of his/her Miranda 10 The Appellate Division has refused to recognize HGN as being scientifically reliable and acceptable, thus allowing its admissibility, without foundational testimony , i.e. a Frye hearing in the trial court.  State v. Doriguzzi, 334 N.J. Super. at 533.  The Appellate Court also refused to recognize the findings made by a Law Division Judge, in State v. Maida, 332 N.J. Super. 564 (Law Div. 2000), following a Frye hearing.  In that case the Law Division Judge found that HGN was scientifically reliable and generally accepted in the scientific community, and therefore, admissible.  State v. Maida, 332 N.J. Super. at 572-3.  Attorney General Guideline: Page 18