2006 Lexus RX 400h Road Test

In addition to recharging the RX 400h's hybrid, high-voltage, sealed nickel-metal hydride (Ni-MH) battery pack,

Lexus' engineers burned the midnight oil when designing the sophisticated hybrid system powering the RX 400h. (Photo: Rob Rothwell, Canadian Auto Press)

regenerative braking supplies nearly all the braking force needed to stop the vehicle. The conventional hydraulic system is only needed during the last few moments of movement when insufficient electricity is being generated to power the brakes. Expect therefore to see much less brake pad wear over the many miles. Partnering-up with regenerative braking in keeping the battery-pack at its optimal level of charge is the V6 engine.

There's little doubt that Lexus engineers burned the midnight oil when designing the sophisticated hybrid system powering the RX 400h, which is impressive in itself, but unless the vehicle meets the performance expectations of Lexus owners, the oil may have been wasted. This is where we, the journalists who risk life and limb to offer opinions in that regard, come in - and here's my opinion: the oil was put to good use. Driving the Lexus hybrid is a pleasure. It outperforms its gas-based sibling, the RX 330, while losing only an inch or so of headroom in the backseat to accommodate the battery pack, and gaining approximately 136 kg (300 lb) of curb weight.

Twisting the key to start the RX400h is a unique and eerily silent experience. The engine does not fire-up; however, the

Bury the right foot and the RX 400h will snap to attention, delivering authoritative acceleration - all with the accompanying serenity expected in a Lexus. (Photo: Rob Rothwell, Canadian Auto Press)

vehicle's enlivened status is verified by a 'Ready' indicator in the gauge cluster. Nudge the throttle and the 400h will stealthily slide away from its position using only its electric motors. Dip a little deeper into the throttle and the gas engine will instantaneously cut-in and boost the acceleration factor. Bury the right foot and the RX 400h will snap to attention, delivering authoritative acceleration - all with the accompanying serenity expected in a Lexus. Its gas engine is a highly polished performer whose presence is unobtrusive unless pushed to the limit, and even then it's smartly muted.