THE ROAD IN RELATION TO TRAFFIC REQUIREMENTS--SPAIN

THE FIRST SUBJECT DISCUSSED IN THE DEVELOPMENT OF THE LIMITATIONS OF THE DESIGN SPEED ON ROADS AND MOTORWAYS, MAKING A DISTINCTION BETWEEN THE CASE OF ROADS IN RURAL AREAS AND THAT OF URBAN THOROUGHFARES. IT IS CONSIDERED THAT IN THE FIRST CASE THE POSSIBLE LIMITATIONS OF THE SPEED OF THE TRAFFIC MUST NOT IMPLY A REDUCTION IN THE DESIGN SPEED. THE PROBLEM IS MORE COMPLICATED FOR URBAN THOROUGHFARES AND RESTRICTIVE SOLUTIONS MAY BE ADOPTED. THE EXISTING STANDARDS FOR THE CROSS-SECTIONS FOR ROADS AND MOTORWAYS ARE THEN BRIEFLY DESCRIBED BOTH IN REGARD TO NORMAL LENGTHS OF ROAD AND AS FAR AS ENGINEERING STRUCTURES ARE CONCERNED; THE MOST INTERESTING CONCEPT OF THE QUESTION DISCUSSED IS THE INVARIABILITY OF THE FILL, THE PAVEMENT AND THE SHOULDERS OF THE ROADS AND MOTORWAYS THROUGHOUT THIER ENTIRE LENGTH, WHETHER THEY EXTEND OVER EARTHWORKS OR OVER ENGINEERING STRUCTURES. UNDER THE HEADING RELATING TO ADDITIONAL TRAFFIC LANES, FOR SLOW-MOVING VEHICLES, AFTER HAVING DEFINED THE CONCEPT OF THESE LANES, THE DIFFERENCES ARE DETERMINED WHICH EXIST BETWEEN THESE ADDITIONAL TRAFFIC LANES AND THOSE WHICH ARE TERMED OVERTAKING LANES AND LANES FOR FAST-MOVING TRAFFIC, WHICH MAY BE ADVISABLE UNDER CERTAIN CIRCUMSTANCES. CONSIDERATION IS ALSO GIVEN TO CASES WHERE LANES FOR SLOW-MOVING TRAFFIC MAY BE NECESSARY, AS WELL AS THE BASIC FUNCTIONAL CRITERIA ON WHICH THE PROJECT SHOULD BE ESTABLISHED. SOME OF THE BASIC CHARACTERISTICS OF THE VERTICAL ROAD SIGNALLING EMPLOYED ON SPANISH ROADS ARE THEN INDICATED AMONG WHICH PARTICULAR INTEREST ATTACHES TO THOSE WHICH HAVE THE COUPLING OF THE INDICATIONS FOR OVERTAKING AND THE CRITERIA OF PROXIMITY FOR THE SELECTIVE INSTALLATION OF SAFETY FENCES. LASTLY, A DESCRIPTION IS GIVEN OF THE FIRST-AID AND BREAKDOWN EQUIPMENTS WHICH HAVE BEEN INSTALLED FOR ROAD USERS ON THE TOLL MOTORWAYS OF CATALONIA IN NORTH-WESTERN SPAIN, WHICH OPERATE BY MEANS OF A SYSTEM OF CODIFIED MESSAGES, AND THE SYSTEM OF TOLL CONTROL WHICH HAS BEEN ESTABLISHED FOR THE GUADARRAMA TUNNEL, TO THE NORTH-WEST OF MADRID, WHICH PROVIDES FOR THE COLLECTION OF THE VARIOUS TARIFFS AND ALLOWS 800 TRANSACTIONS PER HOUR AND PER TRAFFIC LANE, WITH THE CORRESPONDING ECONOMIES WHICH SUCH FIGURES PERMIT.