Protecting Today’s Advanced Bus And Motorcoach Safety Technologies

Mark Holley

By Mark Holley, Director of Marketing and Customer Solutions – Wheel-End, Bendix Commercial Vehicle Systems LLC

Automatic emergency braking (AEB) is a hot topic on the trucking side of the commercial vehicle industry — and it’s one that also has the potential to impact bus and motorcoach fleets by requiring full-stability systems on currently exempted vehicles. These driver assistance technologies — along with others like antilock brakes, active cruise with braking, and steering capabilities — are engineered to deliver safer and more comfortable experiences to the people at the wheel. And getting optimal safety, performance, and return-on-investment from them means making the right decisions in the shop and regarding driver education.

Building On A Proven Past

The foundations of advanced driver assistance system (ADAS) technologies reach back decades to the advent of antilock braking systems (ABS), which have been mandatory since 1988 on air-braked motorcoaches and school buses with a Gross Vehicle Weight Rating (GVWR) of more than 10,000 pounds. During braking, ABS uses wheel speed sensors communicating with an electronic control unit (ECU) to reduce brake pressure at a wheel-end that’s locking up, improving vehicle stability and steerability.

Electronic stability systems are built on ABS technology. Also known as ESP or full stability, these systems add more sensors, delivering the capability to measure driver intent and vehicle direction, as well as addressing roll and directional movement. As a result, ESP can recognize and potentially help drivers mitigate conditions that could lead to rollover and loss-of-control situations.

Although full stability has been required on most new commercial vehicles (including motorcoaches) in the U.S. since 2019, school buses and transit buses remain exempt from this mandate. Still, some North American bus manufacturers offer the technology, and it serves to support advanced driver assistance systems.

Leading-Edge Driver Assistance

Today’s advanced driver assistance systems incorporate a forward-facing radar and camera to deliver driver support such as active cruise control with braking. Benefits like “lane keep assist” are possible when steering torque overlay is added.

Still, no bus or motorcoach safety technology can replace a skilled, alert driver exercising safe driving techniques and proactive, comprehensive driver training. Responsibility for the safe operation of the vehicle remains with the driver at all times, and ADAS technologies are designed to complement safe driving practices.

Although AEB utilizes ABS, full stability, and advanced driver assistance systems, they’re all also dependent on the performance and stopping power at each wheel-end.

Why Brake Type And Friction Matter

Air disc brakes represent the ideal pairing to support these systems, since they provide shorter stopping distances and help drivers maintain control of the vehicle through straighter and more stable stops than drum brakes.

Over repeated braking, air disc brakes demonstrate another advantage over drums through their lack of brake fade. When drum brakes are applied, they generate heat, which expands the drum away from the brake shoe, decreasing the effective stopping power and lengthening the stopping distance. In Bendix testing, a school bus equipped with drum brakes had a stopping distance that was approximately one car length longer than a bus equipped with air disc brakes (stop made at 40 mph with cold brakes). After 20 stops from 60 mph, the stopping distance for the bus with drum brakes was approximately one bus length longer than the bus with air disc brakes.

No matter which type of brake you equip, the right replacement components, including friction, are also vital to ensuring your ADAS technology is performing optimally.

You’ll find no shortage of aftermarket friction options for both disc and drum brakes — but caution is warranted: Not all the friction options out there will meet the stopping distance requirements of Federal Motor Vehicle Safety Standards (FMVSS) 121. The wrong friction can also lead to excessive rotor or pad wear, which means more downtime, higher maintenance costs, and increased brake jobs.

Bendix always recommends using like-for-like components during replacement. These components help maintain the original manufacturer’s braking performance levels and provide protection of your investment in your drivers and vehicles.

Technology & Driver Education — How It All Connects

ADAS features continue to evolve and expand across the North American commercial vehicle landscape: There are highway departure alert and braking capabilities, which can apply the brakes if a system determines the vehicle has left the roadway unintentionally, and multi-lane AEB, which can continually apply the brakes after an automatic braking event in which the driver steers into an adjacent lane where another forward vehicle is detected. Other steering assist options can help compensate for high winds or road crown to ease driver fatigue.

Given the countless situations and road conditions people behind the wheel face every day, it’s vital to ensure that drivers receive proper training on ADAS capabilities and their limitations. Additionally, it’s absolutely necessary to support your driver assistance technologies with effective, reliable, and well-maintained brakes. Protecting your driving team, vehicles, and safety systems isn’t just guarding your investment — it’s helping contribute to safer roads for all who share them.

Mark Holley is Director of Marketing and Customer Solutions – Wheel-End, Bendix Commercial Vehicle Systems LLC. Holley’s career as an accomplished professional with a broad range of practical business experience spans over 25 years in the commercial vehicle industry. He has held numerous key roles in operations, product marketing, and product management in the OEM and aftermarket segments.

Bendix Commercial Vehicle Systems, a member of Knorr-Bremse, develops and supplies leading-edge active safety technologies, energy management solutions, and air brake charging and control systems and components under the Bendix® brand name for medium- and heavy-duty trucks, tractors, trailers, buses, and other commercial vehicles throughout North America. An industry pioneer, employing more than 4,400 people, Bendix — and its wholly owned subsidiary, R.H. Sheppard Co., Inc. — is driven to deliver the best solutions for improved vehicle safety, performance, and overall operating cost. Contact us at 1-800-AIR-BRAKE (1-800-247-2725) or visit bendix.com. Stay connected and informed through Bendix expert podcasts, blog posts, videos, and other resources at knowledge-dock.com. Follow Bendix on X, formerly known as Twitter, at twitter.com/Bendix_CVS. Log on and learn from the Bendix experts at brake-school.com. And to learn more about career opportunities at Bendix, visit bendix.com/careers.