COMPARING EBA BRAKING ALERT TO RADAR TYPE BRAKING ALERT

Radar based brake alert systems depend on the car ahead slowing to detect that the car
ahead car is braking. EBA (Early Brake Alert) detects brake lights coming-on which typically
occurs a couple tenths of a second before the car ahead actually starts slowing.

Sequence of Events and Timing With Radar Systems
Assume a string of 4 cars (C1, C2, C3, C4) are moving along at 70 mph - that's 103 feet per
Second. All times are in seconds and approximate. C1 starts to brake and at T0 (time 0) C1
brake lights (BL) turn-on - radar equipped C2 detects slowing of C1 and alerts driver of C2 at
T0.3 - C2 starts slowing at T1.3 - C3 radar detects C2 slowing and alerts driver of C3 - C3
starts slowing at T2.5 - and at T2.6 driver of C4 is alerted.

Sequence of Events and Timing With EBA System
Assume scenario identical to above. C1 starts to brake and at T0 C1 brake lights (BL) turn-on
- EBA equipped C2 detects BL of C1 and alerts driver of C2 at T0.2 and turns-on C2 BL at
T0.2 - C2 starts slowing at T1.2 - C3 EBA detects C2 BL, alerts driver of C3 at T0.4 and
turns-on C3 brake lights at T0.4 - C3 starts slowing at T1.4 - and at T1.6 driver of C4 is
alerted.

RADAR SYSTEM                     Car 2          Car 3         Car 4   
Time to driver alert                   0.3 sec      1.4 sec       2.6 sec
Time to braking start                1.3 sec       2.4 sec      3.5 sec
Distance traveled @ 70 mph    134 feet     247 feet     361 feet


EBA SYSTEM                            Car 2         Car 3         Car 4   
Time to driver alert                     0.2 sec      0.4 sec      0.6 sec
Time to braking start                  1.2 sec      1.4 sec      1.6 sec
Distance traveled @ 70 mph     124 feet     144 feet     165 feet


SUMMARY
Brake lights exist to provide an early brake alert! Radar based systems don't take advantage
of this and because they depend on the car ahead slowing down to determine need for alert,
cannot overcome the huge life saving advantage of Early Brake Alert.


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