Effect of High Friction Surface Treatment on the Onramp Merging Length

Abstract

The pavement skid resistance, namely the vehicle tire-road contact friction, plays important roles on pavement response, pavement deterioration, traffic operation, and traffic safety. One may find higher tire-road friction surface course is needed or applicable as an effective safety countermeasure for reducing potential traffic crashes and/or collision severity at certain roadway locations, in particular, the ramp emerging or weaving area where foreseeable sideswipe or rear-end collisions might take place between a merging vehicle and another vehicle from the outside lane. A driver should decelerate when merging become difficult as trained in a licensing procedure for avoiding potential collisions. If the required deceleration length is shortened upon avoiding a potential collision, the number of collisions at the onramp should decrease and the collisions if occurred would be less severe. The tire-road frictional coefficient if raised high enough could dramatically reduce the required deceleration length prior to collision, and the high friction surface treatment (HFST) has been introduced in practice for the last decade to shorten the required distance to stop a moving vehicle for both wet and dry road surface conditions. It is of significant interest to examine quantitatively, based on a proposed integrated framework, the effect of a high frictional surface course on reducing the needed deceleration distance, in particular, on an onramp merging/weaving section constructed with limited right of way.