Stopping Distances On Wet Road Surface

Stopping Distance Tests On Wet Road Surface

This test was conducted on January 13, 2001 to approximate the requirements of the March 1, 1997 revision of the FMVSS 121 anti-lock brake system regulation as it pertains to the MSQR-5000^® anti-lock brake system.

The following were pretest assumptions:

1. Since the MSQR-5000^® valve is passive to the brake system (i.e. no moving parts, etc.):

a. The 10-year-old truck with OEM brake system did not need burnishing.

b. The emergency stopping system is a separate system.

2. Wet asphalt taxi way had an approximate skid number of 30.

3. Dry asphalt taxi way had an approximate skid number of 81.

4. An observer in the cab validated the velocity and initiation of braking to an accurate level.

5. A 1984 Trailmobile 48' van trailer simulated a flatbed trailer.

6. OEM brakes:

a. Brake temperatures within specifications.

b. Brake system within code.

7. 1990 Kenworth M-400 tractor brake system within code.

20 MPH Stop Wet Road (32 km)

Stopping Lane 13'-8" Wide (4.2 meters)

Stop 1	15'-2" (4.6 meters)
Stop 2	16'-0" (4.9 meters)
Stop 3	18'-0" (5.5 meters)
Stop 4	12'-6" (3.3 meters)
Stop 5	10'-0" (3.0 meters)
Stop 6	16'-6" (5.0 meters)


60 MPH Stop Wet Road (97 km) Stopping Lane 13'-8" Wide (4.2 meters)

Stop 1	205' (62.5 meters)
Stop 2	215' (65.5 meters)

Vehicle Stability at Stopping

Stopping Lane 13'-8" (4.2 meters)

Left front to left border	3'-1" (.9 meter)
Right front to right border	3'-5" (1 meter)
Left rear to left border	3'-2" (1 meter)
Right rear to right border	3'-5" (1 meter)

Engineer's Notes

The tractor-trailer unit stopped with constant deceleration and the wheels locked only at the point of stopping for all stops..

Conclusion

Although several assumptions were made to simulate a certified FMVSS 121 test, it is obvious that the MSQR-5000^® shows superior (well below maximum allowable) stopping and stability performance in every stop. This demonstration, along with past data, shows this valve more than adequately "ensure(s) safe braking performance under normal and emergency conditions," which is the purpose of FMVSS 121.