SKIDDING-RESISTANCE VALUES USABLE FOR THE DESIGN OF CURVES

IN THE LAST FEW YEARS THE PIJKSWATERSTAAT HAS BEEN ENGAGED ON DRAFTING GUIDELINES FOR THE DESIGN OF MOTORWAYS. WITHIN THIS SCOPE THE WORKING PARTY 'JUNCTIONS' ASKED THE STATE ROAD LABORATORY'S ADVICE ON SKIDDING-RESISTANCE VALUES USABLE FOR THE DESIGN OF CURVES. AN ATTEMPT HAS BEEN MADE TO DRAW UP RECOMMENDATIONS AS COMPLETE AS POSSIBLE BASED ON THE KNOWLEDGE AT THE LABORATORY'S DISPOSAL SUPPLEMENTED WITH DATA FROM LITERATURE. FOR THIS PURPOSE A SIMPLE MODEL OF THE COMBINATION OF FORCES ACTING UPON A VEHICLE THAT RUNS THROUGH A SUPERELEVATED CURVE IS USED. FURTHER CONSIDERATIONS PERTAINED TO THE CHARACTERISTICS OF TYRES, VEHICLES AND PAVEMENTS, ATTENTION ALSO BEING PAID TO CRITERION OF RIDING COMFORT. FINALLY ON ACCOUNT OF THESE CONSIDERATIONS A GRAPHICAL REPRESENTATION OF THE RELATION BETWEEN THE ADMISSIBLE SIDEWAYS FRICTIONAL FORCE AND THE SPEED AT WHICH A CURVE IS TRAVELLED COULD BE DRAFTED.