(A) Section 11-601 of the Illinois Vehicle Code (IVC), being 625 ILCS 5/11-601, specifies statutory speed limits on streets, alleys and highways in rural and urban areas by various classifications of vehicles. Provisions for the altering of these statutory speed limits by the local authority having maintenance jurisdiction or responsibility is defined in 625 ILCS 5/11-604, subject to certain restrictions.
(B) Section 11-304 of the IVC requires all traffic control devices placed by local authorities to conform to the Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD). Section 1A-4 of the MUTCD states the decision to use a sign at a particular location should be based on an engineering study. Therefor, altered speed limits must be based upon an engineering and traffic investigation and appropriate signs giving notice of the altered limit must be erected. Altered speed limits established on the basis of opinions of either public officials or private individuals have no legal authority.
(C) Speed limits, both statutory and altered, are absolute in character, and no motorist may legally exceed such limits at any time, regardless of conditions. Therefor, an altered speed limit shall reflect the optimum, rather than the adverse driving condition, as drivers are subject to citation even though traveling at a speed lower than the posted limit if they are driving at a speed that is greater than is reasonable and proper with regard to traffic conditions and the use of the highway, or endangers the safety of any personal property.
(D) Altered speed limits establish a restraint upon the freedom of the driver to choose a speed at which the driver desires to travel and therefore should be imposed only to the extent that their use will facilitate traffic flow by reducing turbulence in the traffic stream. Driver acceptance is a prerequisite to effective enforcement. If the regulations are imposed only where they are needed and necessary, the driver will more readily accept the need for them. Conversely, an improper or unreasonable low speed limit posting is often violated by the majority of the motoring public, making enforcement of the speed limit completely impracticable, with the resultant operating speeds higher than would exist with a proper and reasonable speed posting.
(E) The installation of all signs regulating speed is detailed in the MUTCD. All signs shall conform to the table of Illinois Standard Signs and the size shall be in accordance with Table A, Sized Designation in the state supplement to the national MUTCD.
(Res. passed 3-13-2007)