There used to be something of a stigma about gas-powered or dual-fuel cars, a feeling that you were somehow going to gain a more cost-effective car at the expense of performance.
The take up rate is still relatively low among new car buyers, but both Ford and Holden now offer LPG-powered versions of their Falcons and Commodores.
We haven't sampled the LPG-only Falcon, but we've just spent a week with Holden's LPG/petrol Commodore Executive V6 Automatic.
And we were impressed, both with the basic VX and with the LPG conversion.
The conversion is done in the factory and adds $1800 to the base model Commodore Executive's pricetag. With the dual fuel option, the Executive costs $43,200.
You can switch between fuel tanks on the move, using a switch to the left of the four-speed automatic gearbox's lever.
Holden says the 3.8-litre V6's power is unaffected by the LPG conversion. It says it has developed LPG-specific engine software. Power remains at 152kW and torque at 305Nm.
In real world use we couldn't distinguish any difference in the way the car performed on petrol or LPG.
It took perhaps a nanosecond longer to fire on LPG, and the engine sometimes felt a little lumpier on idle, but it was the same eager, potent V6 that has given modern Commodores sixes such sparkling performance.
At moderate revs it's a quiet, refined engine, though it gets increasingly raucous if you plant your foot on the accelerator and floor the pedal. At high revs it won't win any prizes for refinement or awards for evocative exhaust note. It delivers a hefty punch, though.
The LPG tank is mounted in the boot, towards the back and under the rear windscreen.
It's relatively-high mounting and the extra weight towards the rear of the car doubtless has some influence on road behaviour, but we didn't detect too much of a pendulum effect.
In fact, we found the Executive an entertaining companion for a brisk afternoon drive - fuelled completely by LPG - in the country.
The grip from the 205/65 RE92 Bridgestones was excellent on dry roads (we drove it only briefly and only in the city and on the motorway when it was raining).
It seems a nonsense to talk of 205s as narrow tyres, but the Executive - a standard car weighs 1526kg - sometimes felt a little under-tyred when pressing on.
The test car had the standard all-independent suspension which gives a supple ride and excellent comfort over bumpy surfaces, but if you were going to be using one on demanding rural roads you might like to fit the added-cost sports suspension.
The basic handling trait is mild understeer, and the independent rear suspension keeps a firm grip on the road.
Pushed hard there's a feeling of tail movement as the body rolls on the suspension and a hint of oversteer developing.
Rear end grip is good, though, and the rear end won't step out - in normal running - without provocation.
Like all big, heavy, cars the Commodore Executive responds best to a light touch. Manhandle it and it becomes unsettled. Use more finesse and it corners and handles very nicely indeed.
In fact we liked the way the car behaved very much and could have spent another couple of hours enjoying its power, responsiveness and entertaining handling.
We like its lively feel and were willing to trade some handling sharpness for the more comfortable ride and entertaining road manners. Sports suspension might tauten matters up but it might also detract from the car's generally user-friendly nature.
The only thing we didn't like about its road behaviour had more to do with its automatic gearbox.
On a demanding winding road, and using the gearbox manually, if you didn't shift into second well before tight corners you could find the car sledging a little as the transmission paused before engaging the lower ratio. It's in situations like that that you appreciate the greater feeling of control a manual gearbox (not available on the LPG Executive) offers.
Steering feel is good and turn-in is crisp. The car holds its line well and the longish-travel and supple suspension copes well with mid-corner bumps.
In fact the Executive's ride is one of its strongest points. It's very smooth and very comfortable.
The four-wheel disc brakes coped well with hard use, though they weren't a patch on the uprated brakes fitted to the Commodore SS we tested recently. Though we had no qualms about the effectiveness of the Executive's stoppers we would have preferred the better feel of the SS's.
Mechanical noise is low unless you're caning the motor and road noise is very low on smooth tarmac. The Bridgestones get more talkative on chip-sealed surfaces.
Wind noise is muted but noticeable at motorway speeds.
Accommodation is spacious in the usual Commodore manner and the seats are well-shaped. We have out doubts about the upholstery fabric, though. It had a tendency to pill like a new household carpet, and strands of hair tended to cling to it like limpets, resisting even industrial-grade vacuum cleaners.
The Executive is the base model so you get wind-your-own windows, but you also get Holden's excellent air-conditioning, a reasonable sound system, central door-locking and other creature comforts. The 15-inch diameter steel wheels come with alloy-look wheel covers, and the mirrors are black rather than body-coloured.
The downside to the LPG Executive is the amount of boot space the tank takes up. It virtually halves the amount of space you've got, though the remaining space is deep and well-shaped. You'd have to decide whether the cheaper big-mileage potential was more important that boot capacity.
Fuel usage? Holden quotes 11 litres per 100 kilometres for the petrol Executive V6 in city running and 6.6 litres/100km in the country.
Its official figures for the LPG model are 16 litres and 9.5.
We figured it would be closer than that. Though we didn't do a fill up of both tanks fuel consumption in our hands seemed broadly comparable.
The petrol tank carries 75 litres, the LPG tank 60, so you've got a car with very great range with both tanks full.
Who buys LPG Commodores? Fleet operators mainly. Holden expects the dual-fuel cars to make up about one to 1.5 percent of VX sales. The police are opting for LPG in front-line Commodores and have ordered around 220.
The option is probably more viable for cars that do high mileages. At the time of writing, LPG was 63.3 cents a litre compared with 116.9 cents a litre for 91-octane petrol. The LPG tank would take around $38 to fill up, and the petrol around $88.
The decision on LPG is a purely economic one: as we've noted there's nothing to choose between the Commodore's performance and behaviour on petrol or LPG. There's certainly no dynamic disadvantage to pay for choosing the gas option.
AutoPoint road test team.