To explore the adverse effects of fog disasters on road traffic in Shanghai, this paper analyzed the spatiotemporal distribution characteristics of fog using daily visibility observations, relative humidity, and other meteorological data from 19 meteorological observation stations in Shanghai, spanning from 2010 to 2020. A risk assessment model was developed based on three key factors: the hazard of disaster, the sensitivity of disaster-prone environments, and the vulnerability of disaster-bearing entities. ArcGIS software was utilized for the analysis and calculation, enabling the completion of the fog risk assessment on roads in Shanghai. Results reveal that the highest incidence of fog disasters on Shanghai's roads occurs from December to February. The peak fog period is between 23∶00 BST and 05∶00 BST, with fog dissipating between 06∶00 BST and 09∶00 BST. The duration of fog at different intensity levels varies. The risk of fog disasters on Shanghai roads is classified into five levels. High-risk sections make up 8.6% of the total expressway/fast road sections in the city and are mainly located in the eastern, western, and southwestern suburbs (of Shanghai). Notable sections include the Jinshan section of G15, the southeast ring and south ring sections of G1503, the west section of G40 Chongming, the Songfeng section of G60, the southern section of S19 Jinshan, the Pudong section of S32, the western section of S36 Jinshan, the southern section of S4 Fengxian, and the Chongming section of the Yangtze River Bridge. Relatively high-risk sections account for 25.8% and are concentrated in the Songjiang and Jiading sections of G15, the east ring section of G1503 and the Tongsan section, the east section of G40 Chongming, the G50 Huqingping section, the middle section of S19 Jinshan, the Songjiang and Minhang sections of S32 and S2, the middle section of S36 Jinshan, and the middle section of Chenhai Highway. Medium-risk sections comprise 26.4%, with notable locations including the north ring section of G1503, the Qingpu section of G2, the Jiading section, the west section of G50 Qingpu, the west section of G60 Songjiang, and the north and south sections of Chenhai Highway. Low-risk sections, accounting for 39.1%, are concentrated in expressways within the outer ring road as well as suburban urban sections like G50 and S4. The distribution of road fog risk provides a basis for implementing risk control measures on Shanghai roads affected by fog.