This study examines the relationship between train traffic and the accident risk for road users at level crossings. The marginal effect of train traffic on the accident risk can be used to derive the marginal cost per train passage that is due to level crossing accidents. Based on Swedish data from 2000 to 2008 on level crossing accidents, train volume and crossing characteristics, the marginal cost per train passage is estimated at SEK 1.13 (EUR 0.11) on average in 2008. The cost per train passage varies substantially depending on type of warning device, road type and the traffic volume of the trains.