THE SAFETY BENEFITS OF 2+1 ROADS AND THEIR FEASIBILITY IN THE CANADIAN CONTEXT

摘要

The “2+1” road, first implemented in the early 90s, is an innovative infrastructure measure usedin several European countries designed to reduce fatal head-on collisions by eliminatingimproper and inattentive overtaking attempts. They are three-lane roads marked in such a waythat the central lane offers the two directions of traffic alternating opportunities for overtaking.Opposing lanes of travel are separated by either a flexible wire rope barrier, or by a double solidline. The primary benefits of 2+1 roads are the overall reduction in the incidence of fatalcollisions and in the severity of collisions in comparison to the regular undivided highways. Thisis thought to be achieved largely by the reduction of driver frustration and a transfer of collisionsfrom the fatal category to the minor injury category. Moreover, the 2+1 road has been known togreatly improve the operational level of service of a road. Canadian road infrastructure is in aposition to greatly benefit from road conversion to the 2+1 format, especially those ruralundivided roads with increased rates of fatal collisions. This new 2+1 road design addressesmany targets that Canada has aimed for in the Road Safety Vision 2010. These sub-targetsinclude:1. A 40% decrease in the number of road users fatally or seriously injured on ruralroadways (defined as two lane roads where the speed limit is 80 - 90 km/h)2. A 20% decrease in the number of road users killed or seriously injured in crashesinvolving commercial vehicles.The main objective of this study was to investigate safety and operational benefits of 2+1 roadsand the feasibility of implementing them on Canadian roads. The research found that there areseveral ideal conditions that need to be present in order to justify the implementation of a 2+1road. These include high traffic volume (low level of service), minimum 6 km stretches of roadwith a limited number of intersections, and no bridges. Alberta conducted a feasibility study on2+1 roads and came to the conclusion that since the majority of Alberta roads are already at avery high level of service with free flow conditions, and have several intersections, it would notbe practical to implement the 2+1 road. Although it is not feasible for Alberta to implement thefull 2+1 road concept, they have implemented the use of adding a passing lane at differentsections of a specific road.