Ruben Zavala v. State, 04-16-00422-CR

Shortly after midnight, Officer Gaitan stopped Ruben Zavala for unsafe lane changes and other traffic violations; Gaitan smelled alcohol and observed red/glassy eyes, slurred speech, and unsteadiness.
On contact, Zavala admitted drinking and using his phone; Gaitan performed part of a field sobriety test and summoned a DWI task-force officer for additional testing.
Gaitan directed Zavala to exit the vehicle; Zavala complied, walked behind his car, dropped an item that Gaitan picked up, and was not handcuffed or placed in the patrol car.
Gaitan asked how much Zavala had to drink, told him he believed Zavala was driving under the influence, conducted a pat-down after asking consent, and instructed Zavala to wait for the other officer.
Zavala moved to suppress oral statements made during the stop, arguing they were the product of custodial interrogation requiring Miranda/article 38.22 warnings; the trial court denied suppression and a jury convicted Zavala of DWI.
On appeal, the Fourth Court reviewed custody de novo (facts undisputed) to determine whether the detention had escalated to a custodial arrest.

Issue	Plaintiff's Argument (Zavala)	Defendant's Argument (State)	Held
Whether statements were made during custodial interrogation triggering Miranda/article 38.22	Zavala: He was in custody once asked to exit the car and the officer opened the door; a reasonable person would feel restrained	State: The stop remained a temporary investigative detention; comments, brief pat-down, and hands-on-patrol-car did not amount to arrest	Court: Not custodial; detention did not escalate to formal arrest, so warnings not required

Miranda v. Arizona, 384 U.S. 436 (Miranda warnings required for custodial interrogation)
Berkemer v. McCarty, 468 U.S. 420 (routine traffic stops are generally noncustodial for Miranda)
Herrera v. State, 241 S.W.3d 520 (Tex. Crim. App.) (Miranda and art. 38.22 apply only to custodial interrogation)
Gardner v. State, 306 S.W.3d 274 (Tex. Crim. App.) (purpose of warnings is to protect privilege against self-incrimination)
Hernandez v. State, 107 S.W.3d 41 (San Antonio Ct. App.) (unwarned custodial questioning requires suppression)
State v. Stevenson, 958 S.W.2d 824 (Tex. Crim. App.) (field sobriety tests during a stop do not by themselves make detention custodial)
State v. Ortiz, 382 S.W.3d 367 (Tex. Crim. App.) (factors for custody determination; no bright-line test)
State v. Sheppard, 271 S.W.3d 281 (Tex. Crim. App.) (distinguishing investigative detention from arrest; relevant factors listed)
State v. Saenz, 411 S.W.3d 488 (Tex. Crim. App.) (appellate standard: defer to trial court on credibility-based facts; legal custody determination reviewed de novo)