Variable　message　sign　(VMS)　seems　to　be　a　good　way　for　traffic　information　releasing　in　fog　weather　because　of　active　luminous.　However,　it　is　still　not　quite　clear　whether　the　normal　text　height　displayed　on　VMS　can　meet　drivers＇　visual　requirements　under　fog　weather.　A　total　of　33　participants　were　recruited　to　test　the　effects　of　text　height　on　drivers＇　visual　characteristic　by　dynamic　driving　simulation　experiments.　Comparison　results　showed　that　the　distance　between　driver　reading　finish　point　and　VMS　(DRFV)　increased　significantly　as　the　text　height　increasing　for　both　normal　and　fog　conditions.　Under　the　fog　conditions,　DRFV,　and　visual　cognition　time　were　slightly　better.　Vehicle　speed　at　reading　finish　point　and　driver　subjective　evaluation　score　for　VMS　under　these　two　weather　conditions　were　not　found　a　significant　difference.　Drivers　tended　to　slow　down　in　advance　to　compensate　for　reduced　visibility　in　fog　conditions.　©　2020　ASCE.