LIMITS OF USE AND DESIGN OF LEFT-TURN LANES ON ROADS OUTSIDE BUILT-UP AREAS

EINSATZGRENZEN UND BEMESSUNG VON LINKSABBIEGESPUREN AN STRASSEN AUSSERHALB BEBAUTER GEBIETE

ACCORDING TO GERMAN SPECIFICATION RAL-K-1-76, THE PROVISION OR OTHERWISE OF LEFT-TURN LANES AT JUNCTIONS DEPENDS SOLELY ON CROSS SECTIONAL LOADING AND SPEED ON THE MAIN ROAD OF THE JUNCTION. IN PART 1 OF THE PROJECT EXAMPLES ARE TO BE TAKEN FROM THE ROAD NETWORK TO SEE WHETHER THESE LIMITS OF APPLICATION ARE ECONOMIC AND EFFECTIVE ON EXISTING ROADS. IT IS ALSO INTENDED TO ESTABLISH WHETHER IN FUTURE THE DECISION TO HAVE LEFT-TURN LANES SHOULD BE BASED ON CROSS SECTIONAL LOADING OR SHOULD ALSO TAKE ACCOUNT OF THE PROPORTION OF TRAFFIC TURNING LEFT. IN THE SECOND PART OF THE WORK THE DYNAMIC MODEL FOR DESIGNING THE LENGTHS OF LEFT-TURN LANES, AS USED IN THE SPECIFICATION, IS TO BE TESTED BY MEASUREMENTS OF THE MOVEMENTS OF LEFT-TURNING VEHICLES. THE OBJECT IS ALSO TO SEE WHETHER THE ESTABLISHED LENGTH OF WIDENED ROADWAY CAN BE SHORTENED AND WHETHER IT IS POSSIBLE AND SENSIBLE TO HAVE A DETAILED DESIGN OF THE LENGTH OF THE LEFT-TURN LANE.