An investigation of fire and explosion hazards of different types of alternativefuel vehicles in tunnels is presented. The different fuels are divided into four types:liquid fuels, liquefied fuels, compressed gases, and electricity, and detailed parameters are obtained. Three types offire hazards for the alternativefuel vehicles: pool fires, jet fires and fireballs are identified andinvestigated in detail. Fromthe perspective of pool fire size, the liquid fuels pose equivalent or evenmuch lower fire hazards compared to the traditionally used fuels, but theliquefied fuels may pose higher hazards. For pressurized tanks, the fires are generally much larger in size butshorter in duration. The gas releases from pressure relief devices and the resulting jet firesare highly transient. Forhydrogen vehicles, the fire sizes are significantly higher compared to CNGtanks, while flame lengths only slighter longer. Investigation of the peakoverpressure in case of an explosion in a tunnel was also carried out. Theresults showed that, for the vehicles investigated, the peak overpressure of tankrupture and BLEVE are mostly in a range of 0.1 to 0.36 bar at 50 m away. Thesituations in case of cloud explosion are mostly much more severe andintolerable. These hazards need to be carefully considered in both vehiclesafety design and tunnel fire safety design. Further researches on thesehazards are in urgent need.