4.7 - SAFESPEED – Speed Management Strategies: an Instrument for the Implementation of Safe and Efficient Road Management Solutions

Project Description

This project aims to develop an integrated methodological approach applicable to the planning and the geometrical and operational design of two lane interurban roads.

Specifically, the aim is to identify a limited number of significantly different road environments justifying the adoption of different speed limits and the implementation of specific flow conditions, and to identify a set of basic criteria which can be used to identify these environments.

Furthermore, for each of them, sets of integrated and standardized, but flexible, road and surroundings design principles and solutions, capable of taking in consideration the different potential traffic levels and cross-sections’ characteristics, will be developed.

Finally, a route oriented evaluation process, capable of assessing the compatibility between the different stretches of road solutions developed along the full length of a route and of predicting and assessing their integrated performance, will also be produced.

For this to be possible there is, however, a need for an improved understanding of the interactions between the different road users namely vehicles/drivers and pedestrians, and between them and both the infrastructure and the surrounding environment, so that the quality of service that a certain road infrastructure can provide to all its users and all the impacts which result from its existence can be better quantified and assessed in an integrated way and efficient solutions can be developed for each type of situation.

Thus, the project begins with the development of analytical models capable of estimating free and average running traffic speeds in two lane roads with different surrounding environments. These models will be a valuable design and testing tool at the standardized road layouts’ development stage, having as reference the FHWA approaches in the HCM2000, but also attending to the problem of predicting speed dispersion patterns.

The speed models will be developed using two different approaches in an integrated way. In the first a driving simulator will be used to test in a controlled environment the different impacts of a number of basic road geometry characteristics. The second one consists of a statistical analysis of the relationships between variables which characterize the geometry, the surrounding environment and the traffic conditions. Also the relationships between road safety and speed as well as between road safety and the roads’ traffic flow, geometry and surrounding characteristics will be studied.

In parallel, statistically based macro safety models will be developed using the real data collected for the development of the speed models and accident data available for the same stretches of roads. Finally the project deals with the development of a multi criteria analysis based methodology to be used in route oriented planning, design and evaluation processes.

Its applicability will be tested through a case study where the existing operational characteristics of a full road itinerary will be evaluated and optimizing infrastructure intervention strategies based namely in traffic calming measures and solutions will be developed and assessed.

Research Team
  • Carlos Rodrigues (Coord. FEUP);
  • António Couto
  • António Lobo
Financial Support
  • FCT (PTDC/TRA/72998/2006)
Stage of Progress
  • Concluded in 2011