RSA 265:9 Obedience to Any Required Traffic Control Devices.

I. The driver of any vehicle shall obey the instructions of any traffic control device applicable thereto placed as provided by law, unless otherwise directed by a traffic or police officer, subject to the exceptions granted the driver of an authorized emergency vehicle in this chapter.
II. No provision of this chapter for which signs are required shall be enforced against an alleged violator if at the time and place of the alleged violation an official sign is not in proper position and sufficiently legible to be seen by an ordinarily observant person.
III. Whenever traffic control devices are placed in position approximately conforming to the requirements of this chapter, such devices shall be presumed to have been so placed by the official act or direction of lawful a