TITLE  49
                                MOTOR VEHICLES
                                  CHAPTER 9
                              VEHICLE EQUIPMENT
    49-948.  RESTRICTIONS AS TO TIRE EQUIPMENT. (1) Every solid rubber tire on
a vehicle shall have rubber on its entire traction surface at least one (1)
inch thick above the edge of the flange of the entire periphery.
    (2)  No person shall operate or move on any highway any motor vehicle,
trailer, or semitrailer having any metal tire in contact with the highway.
    (3)  No tire on a vehicle moved on a highway shall have on its periphery
any block, stud, flange, cleat, spike, or any other protuberance of any
material other than rubber which projects beyond the tread of the traction
surface of the tire, except as allowed herein. It shall be permissible to use
farm machinery with tires having protuberances which will not injure the
highway, and it shall be permissible to use tire chains. Tires with built-in
lugs of tungsten carbide or other suitable material, hereinafter called studs,
may be used upon any vehicle when required for safety because of snow, ice, or
other conditions tending to cause a vehicle to skid, that will not unduly
damage the highway. Motor vehicles, trailers and semitrailers with tires
having built-in studs are prohibited on public highways between the dates of
May 1 and September 30, annually, except as provided in paragraphs (a) and (b)
of this subsection:
    (a)  Fire pumper/tanker trucks and ladder trucks belonging to fire
    departments and firefighting agencies are exempt from the prohibited
    (b)  Special exemptions from the prohibited dates may be granted by the
    Idaho transportation board if it is found by the board that enhancements
    to public safety outweigh the increased pavement wear.
    (4)  Commercial tire retailers shall not sell studded tires with studs
exceeding the following weight and protrusion limitations after July 1, 2005.
Commercial tire retailers and tire shops shall not manually install studs
exceeding the following weight and protrusion limitations after July 1, 2005.
    (a)  Studs shall not protrude more than six-hundredths (.06) of an inch
    from the surface of the tire tread when originally installed.
    (b)  Stud size shall be as recommended by the manufacturer of the tire for
    the type and size of the tire.
    (c)  Studs shall individually weigh no more than one and one-half (1.5)
    grams if the stud is size 14 or less.
    (d)  Studs shall individually weigh no more than two and three-tenths
    (2.3) grams if the stud size is 15 or 16.
    (e)  Studs shall individually weigh no more than three (3) grams if the
    stud size is 17 or larger.

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