*4.1. Vehicle Braking Systems Test on Dry Road*

In this test, we observed the performance of individual braking systems when the vehicle was braking on a straight dry road. The test was performed for the initial vehicle speeds of 100 and 140 km/h. The results of the braking test for the individual braking systems from speed 100 km/h are shown in Figure 10 and Table 3.

**Figure 10.** Test on dry road at speed 100 km/h—(**a**) Speed curve; (**b**) Braking distance; (**c**) Vehicle rotation.


**Table 3.** Test results on dry road at speed 100 km/h.

**Figure 11.** Test on dry road at speed 140 km/h—(**a**) Speed curve; (**b**) Braking distance; (**c**) Vehicle rotation.


**Table 4.** Test results on dry road at speed 140 km/h.

As seen from the test results, all vehicles were kept in their lane and the vehicle with the fuzzy ABS in both cases had the shortest braking distance.

### *4.2. Vehicle Braking Systems Test on Road with Combined Adhesion*

This test was performed on a straight road with different adhesion values for the right and left sides. The left side of the vehicle was on the road with adhesion value 0.2, and the right side of the vehicle on the road with adhesion value 0.5. In general, such combination of surface adhesion represents an icy road. The test was performed for the initial vehicle speeds of 100 and 140 km/h. The results of the braking test for the individual braking systems for speed 100 km/h are shown in Figure 12 and Table 5.

**Figure 12.** Test on road with combined adhesion at speed 100 km/h—(**a**) Speed curve; (**b**) Braking distance; (**c**) Vehicle rotation.

**Monitored Value Without ABS ABS Fuzzy ABS** Braking time (s) 10.5 9.73 9.6 Braking distance (m) 150.52 143.23 141.78 Max. rotation in *z*-axis (deg.) −873.24 −3.21 −2.14

**Table 5.** Test results on road with combined adhesion at speed 100 km/h.

**Figure 13.** Test on road with combined adhesion at speed 140 km/h—(**a**) Speed curve; (**b**) Braking distance; (**c**) Vehicle rotation.


**Table 6.** Test results on road with combined adhesion at speed 140 km/h.

As demonstrated by the test results, a vehicle without an ABS slipped into skidding on the icy road and at both speeds ended off the road. The vehicle with a conventional ABS also skidded at the speed of 140 km/h and finished off turned in the opposite direction. The vehicle with the fuzzy ABS was the only one able to remain on the road and had the shortest braking distance at both speeds.

### *4.3. Vehicle Braking Systems Test When Avoiding an Obstacle on the Road*

In this test, we observed the ability of the vehicle to maneuver on a dry road during braking, employing the individual braking systems. During this test, the vehicle was avoiding an obstacle during braking. The obstacle was simulated by delimiting the route using cones, as illustrated in Figure 14.

**Figure 14.** Road during maneuverability test.

The test was performed for the initial vehicle speeds of 100 and 130 km/h. Because it was important to avoid an obstacle in this test, instead of vehicle rotation in *z*-axis, the shift of the vehicle from the defined route was under observation. The results of this test for individual braking systems at speed 100 km/h are shown in Figure 15 and Table 7.

**Figure 15.** Maneuverability test on dry road at speed 100 km/h—(**a**) Speed curve; (**b**) Braking distance; (**c**) Vehicle trajectory.


**Table 7.** Maneuverability test on dry road at speed 100 km/h.

As seen from the vehicle maneuverability tests during braking at speed 100 km/h, the vehicle with the fuzzy ABS was able to copy the desired trajectory with most accuracy. A vehicle without an ABS would not be able to maneuver when braking, it would just move straight forward with locked wheels and would hit the obstacle.

Figure 16 and Table 8 show the results of test runs at a speed of 130 km/h.

**Figure 16.** Maneuverability test on dry road at speed 130 km/h—(**a**) Speed curve; (**b**) Braking distance; (**c**) Vehicle trajectory.

**Table 8.** Maneuverability test on dry road at speed 130 km/h.


As demonstrated in the vehicles' maneuverability test during braking at speed 130 km/h, the vehicle with the fuzzy ABS was able to copy the desired trajectory most accurately of all the vehicles. The vehicle with the conventional ABS showed problems in copying the desired trajectory at this speed. The vehicle without an ABS would not be able to maneuver when braking, it would just move straight forward with locked wheels and would hit the obstacle the same as before.
