Pavement markings: identification of relevant covariates and controllable factors of retroreflectivity performance as a road safety measure

In this paper we present relevant contributions and important features related to the study of the retroreflectivity performance of pavement markings. The contribution of this paper is threefold. First, we propose an artificial scheme to allow some randomization of the treatments owing to several restrictions imposed on the choice of the experimental units. It is an experiment involving one fixed factor (three types of materials) in a randomized block design executed on a high-traffic-volume highway. Under this condition, the traffic volume works as a stress factor and the degradation of the retroreflectivity of pavement markings is faster than the degradation on rural roads or streets. This is related to the second contribution: the possibility of a reduction of experimental time. The current experiment spent 20 weeks to collect the data. And finally a mixed linear model considering three random effects and several fixed effects is fitted and the most relevant effects pointed out. This study can help highway managers to improve road safety by scheduling the maintenance of pavement marks at the appropriate time, choosing adequate material for the pavement markings and applying the proposed artificial scheme in future studies.