Obedience to devices for control of traffic; exceptions; placement of devices; additional penalty for violation committed in certain zones

1. Except as otherwise provided in NRS 484B.307, it is unlawful for any driver to disobey the instructions of any official traffic-control device placed in accordance with the provisions of chapters 484A to 484E, inclusive, of NRS, unless at the time otherwise directed by a police officer. 2. No provision of chapters 484A to 484E, inclusive, of NRS for which such devices are required may be enforced against an alleged violator if at the time and place of the alleged violation the device is not in proper position and sufficiently legible to be seen by an ordinarily observant person. Whenever a particular provision of chapters 484A to 484E, inclusive, of NRS does not state that such devices are required, the provision is effective even though no devices are erected or in place. 3. Whenever devices are placed in position approximately conforming to the requirements of chapters 484A to 484E, inclusive, of NRS, such devices are presumed to have been so placed by the official act or direction of a public authority, unless the contrary is established by competent evidence. 4. Any device placed pursuant to the provisions of chapters 484A to 484E, inclusive, of NRS and purporting to conform to the lawful requirements pertaining to such devices is presumed to comply with the requirements of chapters 484A to 484E, inclusive, of NRS unless the contrary is established by competent evidence. 5. A person who violates any provision of subsection 1 may be subject to any additional penalty set forth in NRS 484B.130, 484B.135 or 484B.370.