A QUANTITATIVE MODEL OF ROAD-SURFACE SAFETY. Jiangbi Hu , Transportation Research Center , Department of Civil Engineering,Beijing University of Technology , China 2011.5. Contents. Introduction Safety factors in the interaction between vehicle and pavement
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Transportation Research Center, Department of Civil Engineering,BeijingUniversity of Technology, China
Where: Pis the vehicle traction force (kg)；Zω、Zψ、Zj are the air, road, and inertia resistance (kg).
Where:GKis the vehicle load; Ψ is the adhesion coefficient between the tire and pavement.
F2 = FR2 + FT2 (3)
Figure 1: Friction between tire and pavement
Figure 2: Relationship between number of accidents and SFC.
Figure 3:Accident rate versus SFC for rainless & rainy days
Figure 5: SFC as a function of time and location for a certain expressway
(1) maximum longitudinal friction coefficient fTmax
(2) allowable longitudinal friction coefficient fTA (allowed transit friction)
(3)allowable transverse friction coefficient fSA (allowed side friction)
(4) expected longitudinal friction coefficient fTR (required transit friction), and expected transverse friction coefficient fSR (required side friction).
fT—— the longitudinal friction coefficient
FT—— the longitudinal friction
Q —— the gravity.
According to pavement design standard, fTA = 47.
Equation (8) for the quantitative model gave ΔfT values of 14.2, 13.2, 15.48, 4.72, and -10.2
Taking the ΔfT=Min(14.2,13.2,15.48)=13.2 as the critical value, we obtain FB20 ≥ 47 (ΔfS ≤ 0)
Effects of appraise