6-4-2: SPEED RESTRICTIONS:
   A.   Basic Rule:
      1.   No vehicle may be driven upon any highway at a speed which is greater than is reasonable and proper with regard to traffic conditions and the use of the highway, or endangers the safety of any person or property. The fact that the speed of a vehicle does not exceed the applicable maximum speed limit does not relieve the driver from the duty to decrease speed when approaching and crossing an intersection, approaching a hillcrest, when traveling upon any narrow or winding roadway, or when special hazard exists with respect to pedestrians or other traffic, or by reason of weather or highway conditions. Speed must be decreased as may be necessary to avoid colliding with any person or vehicle on or entering the highway in compliance with legal requirements and the duty of all persons to use due care.
      2.   No person may drive a vehicle upon any highway at a speed which is greater than the applicable maximum speed limit established by state law or city ordinance, as may be applicable. (2006 Code § 9-3-3-1)
   B.   Specific Speed Limits:
      1.   Established: Unless some other speed restriction is established as set forth in subsection B3 of this section, the maximum speed limit for all vehicles is:
         a.   Twenty (20) miles per hour through the central business district.
         b.   Thirty (30) miles per hour on streets throughout the remainder of the city, except those under the jurisdiction of the Illinois department of transportation.
         c.   Fifteen (15) miles per hour in an alley.
      2.   Signs Posted: Appropriate signs in compliance with 625 Illinois Compiled Statutes 5/11-604 shall be erected to provide notice of the speed limit through the central business district as provided in subsection B1a of this section.
      3.   Other Increases Or Decreases: Any other increase or decrease of a specific speed limit, if established, shall be in compliance with 625 Illinois Compiled Statutes 5/11-604, as amended from time to time.
      4.   Penalty: Any person convicted of a violation of this subsection B is subject to the penalty provided in section 6-2-5 of this title. (2006 Code § 9-3-3-2)
   C.   School Zones:
      1.   On a school day when schoolchildren are present and so close thereto that a potential hazard exists because of the close proximity of the motorized traffic, no person shall drive a motor vehicle at a speed in excess of twenty (20) miles per hour while passing a school zone or while traveling upon any public thoroughfare where children pass going to and from school. For the purpose of this subsection C, a school day shall begin at seven o'clock (7:00) A.M. and shall conclude at four o'clock (4:00) P.M.
      2.   This subsection C shall not be applicable unless appropriate signs are posted upon streets and highways. The signs shall give proper warning that a school zone is being approached and shall indicate the school zone and the maximum speed limit in effect during school days when schoolchildren are present.
      3.   Nothing in this title shall prohibit the use of electronic speed detecting devices within five hundred feet (500') of signs within a special school speed zone indicating such zone, as defined in this subsection C, nor shall evidence obtained thereby be inadmissible in any prosecution for speeding, provided the use of such device shall apply only to the enforcement of the speed limit in such special school speed zone. (2006 Code § 9-3-3-3)
   D.   Bridges: No person shall drive a vehicle over any bridge constituting a part of a highway at a speed which is greater than the maximum speed which can be maintained with safety to such bridge, when the bridge is signposted. (2006 Code § 9-3-3-4)