Heavy Goods Vehicle (HGV); longitudinal ventilation; fatal vehicle fires in road tunnels (1978-2004); FIRE-SPRINT model; single lane and two lane tunnels; estimates of likelihood (at 2 ms-1) based on test 6 of the HSL test series; posterior probabilities of impingement for a single-lane tunnel; posterior probabilities of impingement for a two-lane tunnel; car and small pool fires; van and medium pool fires