Abstract: Freeways need to be closed or speed-limited in ice and snow conditions，which may lead to problems
such as reducing road capacity and vehicle safety． In order to solve this problem，this paper proposes a variable
speed limit method for freeway under ice and snow conditions based on the characteristics of road alignment，ice
and snow conditions and traffic flow characteristics． A velocity generation model including road alignment and
snow conditions is established，and a fuzzy control system is introduced to predict the snow condition． The
simulation experiment was carried out by Vissim software in some sections of the freeway． The results show that
the variable speed limit method proposed in this paper can dynamically adjusts the speed limit value according to
the snow condition． It reduces the vehicle delay compared with the control groupⅠ ( fixed speed limit) and
improves traffic efficiency and road capacity compared to control groupⅡ( road closure and snow removal + no
speed limit) ． It shows that compared with the traditional method，the proposed method performs better ensuring
the efficiency and safety of highway vehicles under ice and snow conditions．

Key words: intelligent transportation, variable speed limit, fuzzy logic control, freeway, ice and
snow conditions