Blue Bird Vision 2021, Driver'S Handbook Manual

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D R I V E R S H A N D B O O K
Electronic Stability Control
The electronic stability control (ESC) system offers a way to reduce the occurrence of loss-of-control events, as well as rollovers. ESC
builds on the anti-lock brake system (ABS) with additional sensors, logic, and use of the brakes to slow and redirect the vehicle. During
normal driving, ESC continuously monitors steering and vehicle direction. It compares the driver's intended direction, determined by
the measured steering wheel angle, to the vehicle's actual direction determined through measured lateral acceleration, vehicle rotation,
and individual road wheel speeds.
ESC intervenes only when it detects a probable loss of steering control, such as when the bus is not going where the driver is steering.
This may happen, for example, when skidding during emergency evasive swerves, understeer or oversteer during poorly judged turns on
slippery roads, or hydroplaning. ESC estimates the direction of the skid, and then applies the brakes to individual wheels asymmetrically
in order to create torque about the vehicle's vertical axis, opposing the skid and bringing the vehicle back in line with the driver's com-
manded direction. Additionally, the system may reduce motor power to slow the vehicle down.
ESC can function on any surface, wet or dry. It reacts to and corrects skidding much faster and more effectively than the typical human
driver, often before the driver is even aware of any imminent loss of control. ESC systems will alert the driver when they intervene, so that
the driver is aware that the vehicle's handling limits have been reached. An instrument cluster indicator light will illuminate whenever
the ESC system is actively controlling the bus.
The ESC system is not a performance enhancement nor a replacement for safe driving practices, but rather a safety technology to assist
the driver in recovering from dangerous situations. ESC does not increase traction, so it does not enable faster cornering (although it can
facilitate better-controlled cornering). More generally, ESC works within the limits of the bus's handling and available traction between
the tires and road. A reckless maneuver can still exceed these limits, resulting in loss of control. For example, during hydroplaning, the
wheels that ESC would use to correct a skid may lose contact with the road surface, reducing its effectiveness.