RSSplus Has Enhanced Features, Lower Price

Meritor Wabco has an enhanced version of its Roll Stability Support, a stand-alone electronic anti-rollover system for trailers. Called RSSplus, the new system includes event data recording and communications via the powerline connector, and will cost somewhat less than the current product when it becomes available in March, said the joint-venture company's executives in announcing it.

Like RSS, introduced in 2003, RSSplus was adapted for North America from Wabco's European products. It builds on a trailer's anti-lock braking system, which by law it must have anyway, to provide protection against expensive rollovers. It does so by sensing instability in the trailer and applying the brakes, usually in tight turns that the driver has entered too fast. There is no communication with a tractor's ABS or roll-stability system, if it has one; the trailer system works on its own. RSSplus adds "intelligence" with the data recording and PLC communications with the driver in the tractor's cab, said Tom Parrott, engineering manager.

The system's electronic control unit records driving events such as RSS-applied braking, which the owner can use to better manage the driver. Meanwhile, the ECU's brain can learn from severe events to adjust the threshold at which brakes are applied during an RSS "intervention." Other data that can be recorded include tire pressure, wheel-end temperatures and weight at the suspension. These can be sent over the PLC to a display in the cab and, if the owner wants, transmitted to company headquarters via a telemetry service.

The ECU has new connectors that are more positive and prevent incursion of contaminants, which reduces chances of internal corrosion. RSSplus retains standardized SAE diagnostics that customers requested, said Bob Sibley, director of Meritor Wabco Trailer Products. To check or repair the system, technicians can use the company's Toolbox PC software or observe blink codes in a hand-held tool.

RSSplus can be installed on trailers with steel-spring and air-ride suspensions, and with various combinations of sensors and modulators. Its software works on many types of semitrailers, including vans, reefers, tankers, flatbeds and dumps.

It works on B-train doubles, which are connected by a fifth wheel, but not on drawbar-pulled doubles and triples, whose loading characteristics vary widely. Meritor Wabco engineers are devising software to accommodate them, Parrott said.

Trailer builders are charging fleets $700 to $900 for Meritor Wabco's current Roll Stability Support system, but RSSplus should sell for about $200 less, executives said. The prices include ABS, which is part of RSS and RSSplus, so customers should consider that in assessing the worth of a roll-mitigation system, they argued.

Rollovers can be expensive and sometimes catastrophic, so the cost of an anti-rollover system is minor by comparison. The presence of roll-stability interventions on the recorder suggest that the system probably prevented one or more rollovers, and thus more than paid for itself.

RSSplus can be retrofitted to an existing trailer, which might cost $1,200 to $1,500 if the ABS wheel exciter ring and sensors are

already there.

The new wiring should connect to the wheel hardware, so it's a matter of removing the old wiring and ECU and mounting the new pieces; this should take about two and a half hours, Parrott said. Meritor Wabco might have a retrofit program in place by summer.