One of the possible solutions to improve safety on un-regulated pedestrian crosswalks is to use special stop-bars before crosswalks. The aim of these stop-bars is to determine a point, where motorist should stop the vehicle for the pedestrian on a multi-lane roads. The experiment was conducted to determine and calculate the optimal distance, at which the stop-bar should be located before a crosswalk. Experiment was carried out using five different types of motor vehicles, adhesion factor on road surface was measured and calculated. Following article contains experimental data, calculations and conclusions.