EVOLUTION IN THE GEOMETRIC AND TECHNICAL CHARACTERISTICS OF MOTORWAYS

PRESENT REGULATIONS FOLLOW THE ICTAAL (GUIDELINES ON TECHNICAL CONDITIONS OF INTERURBAN MOTORWAY DESIGN: INSTRUCTION SUR LES CONDITIONS TECHNIQUES D'AMENAGEMENT DES AUTOROUTES DE LIAISON) WITH FIXED STANDARDS GOVERNING TRANSVERSE PROFILES AND STANDARDS RELATED TO THE DESIGN SPEED SELECTED FOR PLANE ALIGNMENTS AND LONGITUDINAL PROFILES. THIS RESULTS IN MINIMUM NORMAL CHARACTERISTICS AND ABSOLUTE MINIMUM FOR EXCEPTIONAL CASES. FINANCIAL DIFFICULTIES LEAD TO RESEARCH ON A REDUCTION OF COSTS BUT ENVIRONMENTAL ASPECTS PLAY AN INCREASINGLY IMPORTANT ROLE AND INFLUENCE COSTS MARKEDLY. PRESENT TENDENCIES ARE TOWARDS A RESEARCH ON SUITABLE DESIGN SPEED AND A BETTER UTILIZATION OF THE FACILITIES OFFERED BY ICTAAL. THE MAIN EFFECTS ON THE ENVIRONMENT ARE TEMPORARY AND PERMANENT. IN ENVIRONMENTAL STUDIES INITIAL CONDITIONS MUST BE ANALYZED, THE EFFECTS ON THE ENVIRONMENT EVALUATED, SOLUTIONS COMPARED, AND MEASURES TO BE TAKEN MUST BE DEFINED. THE INFLUENCE OF THE ENVIRONMENT ON GEOMETRIC CHARACTERISTICS IS REFLECTED IN THE SELECTION OF THE DESIGN SPEED AND EARTHWORKS BALANCE. IMPACT STUDIES AND ENVIRONMENTAL PROBLEMS FORM NEW CONSTRAINTS BUT ON THE OTHER HAND PLANNING ENGINEERS HAVE MORE SOPHISTICATED TOOLS FOR THE STUDY. SOME SPECIFIC PROBLEMS SUCH AS DRAINAGE, CONSTRUCTION OF SPECIAL ENGINEERING STRUCTURES FOR PEDESTRIANS, TWO-WHEELERS, AGRICULTURAL MACHINERY AND WILD ANIMALS MUST BE THE SUBJECT OF SPECIAL STUDIES. IT IS CONCLUDED THAT THE QUALITY OF LIFE AND PROTECTION OF NATURE MUST BE CONSTANTLY IN THE MIND OF PLANNERS THROUGHOUT THE PLANNING STAGE. A POSTERIORI INTERVENTIONS MUST BE AVOIDED, AND AN EQUILIBRIUM BETWEEN ENVIRONMENTAL PROBLEMS AND FINANCIAL PROBLEMS MUST BE REACHED.