374 Int. J. Vehicle Performance, Vol. 2, No. 4, 2016 Copyright © 2016 Inderscience Enterprises Ltd. Analysis of the impact of a detached heavy trailer against a concrete median barrier J.A. Romero* Faculty of Engineering, University of Querétaro, Río Moctezuma 249, San Juan del Río, Querétaro, 76800, Mexico Email: jaromero@uaq.mx *Corresponding author A.A. Lozano-Guzmán National Polytechnic Institute, CICATA Queretaro Unit, Cerro Blanco No. 141, Colinas del Cimatario, Santiago de Querétaro, 76800, Mexico Email: alozano@ipn.mx G.M. Arroyo-Contreras and C.S. López-Cajún Faculty of Engineering, University of Querétaro, Centro Universitario, Queretaro, Queretaro, 76000, Mexico Email: marroyoc@uaq.mx Email: cajun@uaq.mx Abstract: Median barriers are road safety devices intended to prevent vehicles from crossing into opposite lanes, bringing them back to the right direction. However, statistics demonstrate that the current concrete barrier designs can cause the rollover of the impacting vehicle. In this context, a case of a vehicle–median barrier impact is represented by a detached trailer that hits a barrier of common design. This impact involves a given sloped surface which the impacting vehicle may climb. In this paper, a 10 degree-of-freedom (dof) model is used to simulate the impact of a detached trailer against a median barrier. While the results show that the rollover can occur as a result of the impact, negligible variations of the maximum roll angle attained are observed when changing the impact angle and the vehicle speed. Future research efforts should be made to assess the heavy vehicles rollover potentials of current median barriers designs. Keywords: detached trailers; concrete median barrier; impact angle; impact speed; fifth wheel; vehicle dynamics; Rocky mountain doubles; road safety; vehicle rollover.