An Arizona-based dealership and a school bus manufacturer are working to bring an active suspension system to school districts in the state with the aim of providing smoother rides for students and drivers alike.

RWC Group, a bus and commercial truck dealership in Phoenix, is now selling IC Bus Type C buses equipped with LiquidSpring, a compressible liquid adaptive suspension system that can automatically adjust the floor level in response to rough roads and driving maneuvers such as swerves and sharp turns, and provide stability to even out the drive.

Riding on a bus with the system could be especially beneficial for special-needs students who may be more impacted by these road conditions. The system can also enhance driver comfort and help reduce fatigue, say bus drivers who have taken a bus outfitted with the system for a test drive.

Adaptive Suspension

Travis Ward, national bus sales representative for LiquidSpring LLC, the company that created and sells the product of the same name, says that the system provides a seamless ride by employing a shock-absorbing liquid boosted by smart controls to access the right-sized spring for every second of the ride instead of using a one-size-fits-all metal spring solution.

LiquidSpring’s system also includes special valving and a computer control unit with an algorithm that continuously monitors the suspension and adjusts within fractions of a second. A five-link suspension allows the axle some movement, which passengers typically cannot feel, under the bus. Additionally, a microprocessor optimizes the ride based on the vehicle’s steering direction, speed, braking level, and the motion at each wheel. It also senses sharp turns or evasive maneuvers and stiffens in milliseconds to improve handling.

“Driving straight down the road, you would want [the suspension] to be super soft so you absorb the road conditions,” Ward explains. “When you go into a corner and have a high center of gravity, you would want a stiffer suspension so you don’t feel the bus have what’s called body roll or rocking. LiquidSpring can go from super soft to super firm in fractions of a second.”

The system doesn’t just offer comfort, Ward says; it can also alleviate driver fatigue that stems from driving in extremely windy conditions, bolster passenger safety during sharp turns, and decrease pain for special-needs riders. Additionally, less chassis maintenance is needed because the suspension system reduces frame flexing issues for enhanced stability.

LiquidSpring is currently optional equipment and is only available on IC Bus’s Type Cs, Ward says.

The company, which created the LiquidSpring strut over 20 years ago for off-highway mining trucks and provides the adaptive suspension system for ambulances, RVs, mining equipment, and transit buses, is in the early stages of bringing its suspension system to the school bus market.

Partnership

Sudha Veerapaneni, the product marketing director for IC Bus, says that the relationship between LiquidSpring and IC Bus came about after Navistar engineering and IC Bus dealer personnel came across the suspension system at trade shows and other commercial vehicle events. Navistar then released the LiquidSpring suspension as an option on IC Bus’s Type C school buses and two medium-duty International truck models.

“We have specifically seen interest for school buses and ambulances on the truck side of Navistar’s business,” she says.

So far, two buses have been built with the LiquidSpring suspension. There would be a significantly higher cost to install this suspension retroactively, but it is possible, Veerapaneni adds.

Easier Ride, Less Fatigue

Veerapaneni took one of the buses equipped with the system for a ride in November and attests to the comfort it offers.

“The LiquidSpring suspension provided a smoother ride in comparison to other suspensions we offer on our buses,” Veerapaneni says. “Another feature that I believe customers would value is the ride height adjustment option.”

Tom Hartman, general manager, bus, for RWC Group, says that LiquidSpring’s Ward contacted him in early 2018 after one of RWC’s customers, the Arizona State Schools for the Deaf and Blind, expressed interest in buying a school bus with the suspension system. Ward also brought the dealer a demonstration bus to drive.

Albert Duff, facilities and transportation manager of the Tucson campus at the Arizona State Schools for the Deaf and the Blind, says that the school system is considering future orders of buses equipped with the system after riding on a demonstration bus in late 2017.

The school system transports 100 students daily and 50 students for its major homegoings (when it sends its residential students home for a week) every six weeks to remote locations in the state. Those longer trips can be on rougher roads, causing more fatigue.

“[The system] would provide improved comfort for both our students and drivers,” he adds. “This includes a smoother ride that has less noise and wear and tear on the bus.”

Meanwhile, RWC has demonstrated an IC bus with the LiquidSpring system to several school districts in the state and received a favorable response, Hartman says.

Chris Miller, the lead mechanic at Saddle Mountain Unified School District in Tonopah, Ariz., along with Andrew Pariga, a bus driver for the district, drove the bus during a Jan. 10 demonstration and said that it eased the ride on rugged roads in the rural area they serve, which is about 52 miles west of Phoenix. The district’s drivers often navigate dirt roads riddled with potholes, streams left by rain, and dips.

“We took it down our special-needs routes and some rough roads, and there was a night-and-day difference,” Miller says. “The system smooths every bump, so the ride is not so harsh.”

Driving the demonstration bus outfitted with the system was also easier on his back, Pariga says.

“The suspension system works in the front too, making the ride comfortable for the driver as well as the students.”

Pariga also pointed to the ability to lower the rear of the bus in case of an emergency, to evacuate special-needs students faster, as a plus.

The district has ordered two of the Type C buses with LiquidSpring to serve the more than 100 special-needs students who attend the school district, Miller says.