Section 349.11 - Authority to modify speed restrictions(1)(a) Whenever the department with respect to the state trunk highway system and the local authorities with respect to highways under their jurisdiction determine upon the basis of an engineering and traffic investigation that any statutory speed limit is greater or less than is reasonable or safe under the conditions found to exist upon any part of a highway or that the actual speed of vehicles upon any part of a highway is greater or less than is reasonable and prudent, the department with respect to the state trunk highway system and the local authorities with respect to highways under their jurisdiction may, subject to the limitations set forth in subs. (2) and (3), determine and declare a reasonable and safe speed limit on the highway or part thereof in question. When appropriate signs giving notice of such speed limit have been erected and are in place, such speed limit shall be effective at all times or at such times as indicated by the signs.(b) Whenever the department with respect to the state trunk highway system determines, upon the basis of an engineering and traffic investigation, that any statutory minimum speed limit is greater or less than is reasonable or safe under the conditions found to exist upon any part of a highway or that the actual minimum speed of vehicles upon any part of a highway is greater or less than is reasonable and prudent, the department with respect to the state trunk highway system may, subject to applicable limitations in subs. (2) and (3), determine and declare a reasonable and safe minimum speed limit on the highway or part thereof in question. When appropriate signs giving notice of such minimum speed limit have been erected and are in place such minimum speed limit shall be effective at all times or at such times as indicated by the signs.(2) The department may not do any of the following:(a) Declare a speed limit which is in excess of the limits stated in s. 346.57 (4) (h), except as provided in s. 346.57 (4) (gm).(b) Modify the limits stated in s. 346.57 (4) (c) or 346.58.(c) Modify the statutory speed limit on more than 2,000 miles of state trunk highways. The first mile outside of and immediately adjacent to any incorporated municipality shall not be counted in computing such 2,000 miles. This paragraph does not apply to freeways or to expressways, as defined in s. 346.57 (1) (ag) and (am).(3) Local authorities may not: (a) Declare a speed limit which is in excess of the limits stated in s. 346.57 (4) (h); or(b) Modify the limits stated in s. 346.57 (4) (c) or 346.58; or(c) Modify any existing speed limit without the consent of the department except to reduce the speed limit as provided under sub. (10), or to increase the speed limit stated in s. 346.57 (4) (e), (f) or (g), or to reduce by 10 miles per hour or less the speed limit stated in s. 346.57 (4) (a), (b) or (d) to (j), or to reduce by 15 miles per hour or less the speed limit stated in s. 346.57 (4) (k). Whenever department approval is required, no signs giving notice of a modification of the speed limit may be erected until such approval has been received.(4) The department upon request from any county highway committee or local authority shall, or upon its own initiative may, conduct an investigation of any bridge, causeway, viaduct or structure on any highway. If it finds that any such structure cannot with safety to itself withstand vehicles traveling at the speeds otherwise permitted by law or if it finds that such structure is substandard as to width and that it is necessary from the standpoint of traffic safety to reduce the speed of vehicles using such structure, the department shall determine and declare the maximum vehicular speed which such structure can withstand or which can be maintained in safety on such structure. When appropriate signs giving notice of such maximum speed have been erected at a suitable distance before each end of the structure, such posted speed limit is the effective speed limit on such structure at all times when the signs are in place. The findings and determination of the department are conclusive evidence of the maximum speed which can be maintained with safety to or on any such structure.(5) Except as provided in sub. (10), the department and local authorities shall place and maintain upon all highways, where the speed limit is modified by them pursuant to this section, standard signs giving notice of such speed. All speed limit signs so erected shall conform to the rules of the department.(6) No liability shall attach to the department or to any local authority by reason of the posting of a speed limit pursuant to this section nor shall such posting guarantee that the posted speed is reasonable and safe under all conditions.(7) The department with respect to the state trunk highway system and local authorities with respect to highways under their jurisdiction may increase the speed limits stated in s. 346.57 (4) (a) and (b), but any speed limit so established shall not be greater than the speed limit established on the adjoining sections of the same street or highway.(8) Notwithstanding the authority otherwise granted to modify speed restrictions in this section, except as provided in sub. (9) and s. 346.57 (4) (gm), the department may not establish or continue: (a) A maximum speed limit on any highway within its jurisdiction in excess of 55 miles per hour;(c) Maximum speed limits which are not uniformly applicable to all types of motor vehicles using a highway, except that a lower speed limit may be established for any vehicle operating under a special permit because of any weight or dimension of such vehicle.(8m) Notwithstanding the authority otherwise granted to modify speed restrictions in this section, local authorities may not establish or continue:(a) A maximum speed limit on any highway within their respective jurisdictions in excess of 55 miles per hour;(c) Maximum speed limits which are not uniformly applicable to all types of motor vehicles using a highway, except that a lower speed limit may be established for any vehicle operating under a special permit because of any weight or dimension of such vehicle.(9) The department, with respect to any highway, may alter speed restrictions during an energy emergency to comply with federal law or if the department finds that extraordinary circumstances in this state require such alteration. All decisions made by the department under this subsection will be subject to review by the joint committee for review of administrative rules in accordance with s. 227.26.(10) Notwithstanding any speed limits imposed under this section or under s. 346.57, if a highway is being constructed, reconstructed, maintained or repaired, local authorities with respect to highways under their jurisdiction, any county highway committee performing maintenance on the state trunk highway system under s. 84.07 and any local authority with respect to highways not under its jurisdiction that are being constructed, reconstructed, maintained or repaired by the local authority may, for the safety of the highway construction and maintenance workers, pedestrians and highway users, post a temporary speed limit less than the speed limit imposed under this section or under s. 346.57. The temporary limits may be posted for the duration of the construction, reconstruction, maintenance or repair period. Temporary speed limits imposed under this subsection may be posted with signs on portable supports. When portable supports are used under this subsection, the bottom of the sign shall be not less than one foot above the surface of the pavement or shoulder.(11) Notwithstanding any speed limits imposed under this section or under s. 346.57, if a local authority designates a highway under its jurisdiction as an all-terrain vehicle route under s. 23.33 (8) (b), the local authority may post a speed limit, applicable only to all-terrain vehicles and utility terrain vehicles, as defined under s. 23.33 (1) (ng), that is lower than the speed limit imposed under this section or under s. 346.57.Amended by Acts 2021 ch, 164,s 2, eff. 3/13/2022.1971 c. 38; 1973 c. 157; 1975 c. 25; 1977 c. 29 s. 1654 (8) (a); 1977 c. 30 s. 5; 1977 c. 67, 203, 418; 1979 c. 213; 1983 a. 54; 1985 a. 182 s. 57; 1987 a. 17, 219; 1989 a. 31; 1993 a. 376; 1995 a. 318; 1999 a. 85.