1. 0.80 0.85 0.90 0.95 1.00 1.05 1.10 ABC Proving ground PFC value (ASTM1136) Comparison between K value and PFC value on Dry surface Fig. 1 ： Friction Coefficient between typical proving ground Fig. 2 ： The Ratio of K-value to PFC value for passenger cars 0.8 0.9 1 1.1 1.2 1.3 123456 (K value)/(PFC value) Proving Ground A Proving Ground B Proving Ground C : PFC (ASTM1136) = 195/75R14 （ M/L Tiger Paw)= : K value (1~ 6; different vehicle) 1; 225/50R18 2; 215/65R16(M+S) 3; 175/65R14(AS) 4; 205/55R16 5; 215/45R17 6; 205/50R17 The surface friction difference between proving ground is small. (A-C: 6%) K-value shows higher than PFC. The difference depends on the tyre performance. GTR-ESC-2007-10-A1 (1)

2. 1. Contents of Study: - The comparison of lateral displacement on the different surface friction coeff. (0.8, 0.9, 1.0) by using simulation of the Sine with Dwell test without ESC operation was done by several Japanese car manufactures. (condition: Vehicle speed; 80 km/h, Steering wheel angle; 5x(0.3G steer angle)) Lateral Displacement Influenced by Surface Friction(1) Vehicle Wheel BaseWeight Tyre FR P-car ： A SUV ： L FF P-car ： B SUV ： M FF P-car ： C SUV ： N FF P-car ： D SUV ： O FF P-car ： E SUV ： P FF P-car ： F SUV ： Q SUV ： R FF P-car ： G A B C D E F G H 1533 1991 1570 1690 1520 2280 1659 2172 1375 1515 1400 1700 958 1896 205/55R16 235/55R18 205/50R17 205/60R16 215/50R17 245/50R20 215/55R17 265/50R20 235/45R17 225/55R18 215/45R17 215/55R17 175/65R14 225/65R17 2730 2720 2700 2900 2730 2880 2635 2670 2620 2440 2640 2775 2850 Simulation software CarSim In-house soft veDYNA CarSim ADAMS/Car ADAMS In-house soft [mm] [kg] (2)

3. Lateral Displacement Influenced by Surface Friction(2) 2. An Example of time history data (Passenger Car) -0.5 0 0.5 1 1.5 2 2.5 3 [s] [deg] 120 0 -120 1.07 Steering Wheel Angle [m/s ] 10 0 -10 2 SWA[deg]  = 0.8  = 0.9  = 1.0 Lateral Acceleration -0.5 0 0.5 1 1.5 2 2.5 3 [s] Fig 3 ： Time history data of passenger car [m] 6 0 -6 Lateral Displacement -0.5 0 0.5 1 1.5 2 2.5 3 [s] SWA[deg]  = 0.8  = 0.9  = 1.0 The influence of surface friction to the lateral displacement is small, because and are canceled each other. 0.9 1 1.1 1.2[s] 2.94 2.74 -2.0 -3.5 [m] (3)

4. Lateral Displacement Influenced by Surface Friction(3) 3. All results 1.5 2 2.5 3 3.5 0.80.91 Friction coefficient (  ) Lateral displacement [m] Fig 4 ． The influence of the surface friction to the lateral displacement P-car : A P-car : B P-car : C P-car : D P-car : E P-car : F P-car : G SUV : L SUV : M SUV : N SUV : O SUV : P SUV : Q SUV : R Ave. difference: 15cm  @0.9 -  @0.8 = 18 cm  @1.0 -  @0.9 = 13 cm (4)

5. = Reference : The testing error range (1)= 22 [cm] ∫∫AYCG ・ dt ・ dt @ 1.07s [m] 5 1 2 3 4 6 7 8 9 10 The tyre lot No. 2.5 2.4 2.3 2.2 2.1 2.0 Fig 5 ． An Example of the error range of driving test by different lot number of tyres (5)

6. “Lateral Displacement” for SWAN > 5 Least sensitivity to temperature (ΔT = 489 for 302) High S/N (11.0) 4 significant track differences From NHTSA docket:No. 25801-9 = Reference : The testing error range (2) = (6) 20cm 18cm