Recently, the Calif.-based Riverside Transit Agency (RTA) rolled out a hydraulic hybrid system aboard a 12-seat vehicle that harnesses energy during the braking process to propel the vehicle when it accelerates, resulting in less brake maintenance, reduced operating costs, better fuel economy and fewer harmful emissions.

"In regular stop-and-go traffic, when you take your foot off the throttle, the vehicle will slow very quickly and, when you're ready to accelerate, you don't have to put a lot of pressure on the pedal; you just hit it and it's ready to go," said Bob Bach, director of maintenance.

RTA began work in earnest on the project last spring, following nearly three years of collaborating with hydraulic manufacturer Eaton Corp. The installation of the Eaton test unit, which is placed right behind the transmission of an ElDorado National vehicle, was conducted by the Riverside-based bus remanufacturing and retrofit company Complete Coach Works — the company which previously refurbished RTA's trolleys.

"As part of our piece of the pie here, we have to supply a vehicle and report information on the vehicle monthly, whether it's fuel mileage, number of miles run, maintenance difficulties, so on and so forth," Bach said. "The concept has been around for a long time, bus this is one of Eaton's first tests outside of the military."

Eaton is using RTA's test bus in an at-tempt to find out if it is financially feasible to put the solution onto a vehicle and get a beneficial cost of return on it, as well as how much will be saved in emissions, fuel and brake wear. The group also partnered with nearby University of California, Riverside, to conduct testing before, during and after implementation of the hydraulic hybrid system.

"RTA is always exploring new and innovative ways to deliver our service," said RTA Chairman of the Board Bob Buster. "This particular project is the result of RTA's commitment to pushing the limits of technology and making a real difference in terms of reducing harmful emissions."

The bus, which will operate on various routes, was made possible by Congressman Ken Calvert (R-CA), who endorsed a funding request by CALSTART, a California-based clean transportation consortium, for nearly $500,000 in Federal Transit Administration and South Coast Air Quality Management District funding.

Following the one-year test of the bus, RTA will remove the Eaton system and return the vehicle back to normal, with the company supplying the agency with a report of the test results, explained Bach.

"If the technology proves to be something that we find to be valuable, it is possible it could potentially spread to the rest of our fleet," said Bach. "It is quite possible that once you retire the vehicle, you can take this unit off and install it on the next new vehicle. To me, that would really make sense for our return on investment."

This recent test adds to RTA's long alternative-fuel history.

In 1988, prior to today's laws that regulate bus emissions, RTA was among the first transit systems in the nation to operate low-emission methanol buses, including the installation of a separate fueling system for alternative clean fuels when RTA's Riverside headquarters was built in 1986.

Additionally, in 2001, the agency re-placed its entire fleet of diesel buses with compressed natural gas buses.