LIMITING VALUES FOR ALIGNMENT OF LONGITUDINAL SLOPES, THE ROUNDING OF DIPS AND SUMMITS, IN CONNECTION WITH GRADE-SEPARATED JUNCTIONS

TRASSIERUNGSGRENZWERTE FUER LAENGSNEIGUNG, KUPPEN- UND WANNENAUSRUNDUNG IN VERBINDUNGSRAMPEN PLANFREIER KNOTENPUNKTE

THE LIMITING VALUES FOR PROFILE ALIGNMENT GIVEN IN THE RECOMMENDATIONS FOR THE EXPANSION OF RURAL ROADS, PART 2: ALIGNMENT (RAL-L) FOR OPEN SECTIONS HAVE SO FAR BEEN GENERALLY USED FOR ACCESS ROADS AT GRADE SEPARATED JUNCTIONS. THIS LED TO EXCESSIVE DEVELOPMENT LENGTHS, WHICH ESPECIALLY IN CONGESTED AREAS AND IN THE CASE OF UNFAVOURABLE GRADES ON THE ROADS TO BE LINKED, COULD ONLY BE REALIZED WITH DIFFICULTY. THE AIM OF THE RESEARCH IS TO CLEAR UP THE QUESTION AS TO WHETHER, FOR THE DETERMINATION OF LIMITING VALUES FOR PROFILE ALIGNMENT OF ACCESS ROADS, BECAUSE OF THE DIFFERENT TRAFFIC FLOW COMPARED WITH THAT ON OPEN SECTIONS, AND TAKING INTO ACCOUNT THE SUPERPOSITION OF THE LAYOUT AND PROFILE PLANS, A DIMENSIONING MODEL MIGHT NOT BE USED WHICH DEVIATES FROM THE RAL-L. PROGRAMME. 1. CHECKING OF THE RAL-L DRIVING DYNAMIC DIMENSIONING MODEL FOR DIPS AND SUMMITS IN RESPECT OF THE SPECIAL CONDITIONS OF ACCESS ROADS. SEPARATION OF THE MOST IMPORTANT FROM THE LESS IMPORTANT INFLUENCING FACTORS WITH THE AID OF SIMULATION AND VARIATION OF PARAMETERS. 2. VERIFICATION OF THE IMPORTANT FACTORS BY EVALUATION OF THE RESULTS OF RESEARCH AVAILABLE IN THE LITERATURE, AND SUPPLEMENTARY SIMPLE MEASUREMENTS. 3. STUDY OF THE INFLUENCE OF OPTICAL CRITERIA ON THE LIMITING VALUES FOR ALIGNMENT IN PROFILE (SUPERPOSITION OF LAYOUT AND PROFILE PLANS, THE EFFECTS OF VEHICLES AHEAD ON VISIBILITY). 4. A STUDY OF THE PROBLEM AS TO THE EXTENT TO WHICH ANY DISADVANTAGES OF MINIMAL ELEMENTS IN THE PROFILE OF ACCESS ROADS CAN BE COMPENSATED BY SPECIAL MEASURES IN THE ACCESS AND EXIT ROADS (E.G. LENGTHENING OF THE MERGING AND LEAVING LANES). 5. A STUDY OF THE REASONS GIVEN IN THE LITERATURE FOR FOR MAXIMUM SLOPES, TAKING INTO ACCOUNT THE SPECIAL CONDITIONS IN ACCESS ROADS. 6. THE WORKING OUT OF LIMITING VALUES FOR SLOPES, DIP AND SUMMIT ROUNDING IN LINK ROADS, IF NECESSARY IN CONJUNCTION WITH DIFFERENT LOCAL AND TRAFFIC CONDITIONS.