Method for Assessing Safety of Routes in a Road Network

Abstract

In the Netherlands, the concept of sustainably safe traffic is the leading vision in road safety policy and research. The main goal of a sustainably safe road transport system is to reduce the annual number of road accident casualties to a fraction of the current levels. Important requirements resulting from this vision are that trips follow safe roads as much as possible, trips be as short as possible, and the quickest and safest routes coincide. Modeling route choice will provide answers to the planning issues of sustainably safe traffic; however, the safety effects of these requirements constitute a totally different issue, which needs to be dealt with. The focus of this study is on the design of a method that enables the planner to determine the safety effects of existing route choice and the changes in route choice. A description of road safety can be made in various ways. When a microscopic model is used, conflicts between vehicles will be an integral part of the simulation. The outcome will be used to compare the types of conflicts in a given simulation with the types of conflicts that would be acceptable in a sustainably safe road environment, for example, conflicts with opposing vehicles should be minimized at high speed differentials. A so-called route diagram of each route can be checked according to a series of criteria, each representing requirements for a sustainably safe route choice. Each criterion of the route diagram contributes to the total safety level of a route by the number of demerit points scored by the criterion. The criteria are described and tested in a microsimulation of alternative routes in a synthetic road network.

Sensitivity analysis on heterogeneity of driving behavior for evacuation studies and its impacts on traffic safety

“…These indicators include, for example, time-to-collision, speed difference between successive vehicles, gap distance between vehicles, etc. The Time-To-Collision (TTC) notion has been applied beneficially as a safety indicator in safety analysis [12,13]. A TTC value at a time instant t is defined as the time that remains until a collision between two vehicles would occur if the collision course and speed difference are maintained.…”

Derivation and Validation of New Simulation-Based Surrogate Safety Measure

“…Furthermore, these two indicators were also integrated in a VISSIM model to analyze the improvement of performance of an improved incident reduction function for the driver's dilemma in an actuated signal-control intersection (10). When the safety performance of different route choice decisions in road networks are compared, two networkwide safety measures, namely TExT-IT and TInT-VR, are obtained by dividing TExT and TInT by the number of involved vehicles counted during the simulation period (11).…”

Determination of the Safest Route for Logging Trucks Based on Road Types and Conditions

“…In the solution process of forest transportation planning with minimum cost, various parameters such as road length, travel time, and transportation unit cost are assigned to the road links, and then the optimal path is determined by searching the alternatives [8]. In order to search for transportation planning with safety constraints, specific parameters such as road standards and road conditions should be taken into consideration [9].…”