I found this on http://codes.ohio.gov/orc/4513.03
4513.03 Time for lighted lights on motor vehicles.
(A) Every vehicle, other than a motorized bicycle, operated upon a street or highway within this state shall display lighted lights and illuminating devices as required by sections 4513.04 to 4513.37 of the Revised Code during all of the following times:
(1) The time from sunset to sunrise;
(2) At any other time when, due to insufficient natural light or unfavorable atmospheric conditions, persons, vehicles, and substantial objects on the highway are not discernible at a distance of one thousand feet ahead;
(3) At any time when the windshield wipers of the vehicle are in use because of precipitation on the windshield.
Every motorized bicycle shall display at such times lighted lights meeting the rules adopted by the director of public safety under section4511.521 of the Revised Code. No motor vehicle, during such times any time specified in this section, shall be operated upon a street or highway within this state using only parking lights as illumination.
Whenever in such sections a requirement is declared as to the distance from which certain lamps and devices shall render objects visible, or within which such lamps or devices shall be visible, such distance shall be measured upon a straight level unlighted highway under normal atmospheric conditions unless a different condition is expressly stated.
Whenever in such sections a requirement is declared as to the mounted height of lights or devices, it shall mean from the center of such light or device to the level ground upon which the vehicle stands.
(B) Notwithstanding any provision of law to the contrary, no law enforcement officer shall cause the operator of a vehicle being operated upon a street or highway within this state to stop the vehicle solely because the officer observes that a violation of division (A)(3) of this section has been or is being committed or for the sole purpose of issuing a ticket, citation, or summons for a violation of that division, or causing the arrest of or commencing a prosecution of a person for a violation of that division.
(C) Whoever violates this section is guilty of a minor misdemeanor.
Amended by 128th General AssemblyFile No.9, HB 1, §101.01, eff. 10/16/2009.
Amended by 128th General Assemblych.9, HB 2, §101.01, eff. 7/1/2009.
Effective Date: 01-01-2004
Not only is it the law, here in Ohio, but it is common sense. You make yourself as visible as possible when driving.