Quantitative assessment and prevention for car-following risk on foggy bridge based on field theory

The superimposed impacts of bridge and fog on car-following risk remain unclear. The study proposed a risk-field-guided quantitative framework integrating risk assessment and prevention. We designed the ordinary road, ordinary bridge, and foggy bridge to conduct driving simulation experiments. Risk field force models were developed to quantify car-following risk. A targeted prevention strategy was designed and validated for the foggy bridge. Results reveal that: (1) Bridges exacerbate the heterogeneity in speed and impairs drivers′ cognition. Fog destabilises the car-following process and deteriorates behaviour performances on bridges; (2) On bridges, lower car-following risk reflects compensatory driving behaviours, rather than lower risk due to bridge-specific road conditions. On foggy bridges, drivers exhibit excessive following tendencies with inadequate behavioural compensation, resulting in the highest risk; (3) The prevention strategy effectively alleviates car-following risk on foggy bridges. The study offers a theoretical foundation and application guidance for bridge safety management.