Every now and again we all run cars with the fuel light on or watch the miles left in the tank go down.

This happened to me today in a Volkswagen Golf GT Sport as I was driving along the A34.

I came across a petrol station but it was closed for refurbishment. Playing a game of chance, I carried on and joined the M40, at which point the trip computer dropped to zero miles left.

When I got back to the office I called a few manufacturers to see what zero actually meant.

They all had the same answer – they don’t really know. But they all know that the trip-computer software is designed to allow for a safety period.

They all believe that there is normally around three to four litres of fuel left when zero is shown – regardless of the engine size or whether it’s petrol or diesel.

This means that a small diesel car will go much further than a large petrol one.

The car manufacturers also try to keep the distance to a minimum as when the tank is filled up, the driver likes to see a huge distance range appear on the trip computer.

If they built in 100 miles when the tank is showing empty, then the range would be much reduced, so they want to get a fine balance.

I did make it to the motorway services, paid silly prices, and the moral of the story is – keep your tank tanked up.

Smart sent up a new ForTwo Pulse, one of only a handful in the UK, for me to try.

The car was left-hand drive and German-registered, so not only can you park it anywhere because it’s so small, but I could park it anywhere because traffic wardens hate dealing with foreign-registered vehicles.

I took it for a run to Coventry and was impressed at the way it got up to motorway speeds, and felt safe and comfortable while at speed.

I last drove a new Smart on the international press launch in and around Madrid.

I liked it then and liked it even better around Huddersfield.

The new model is light years ahead of the current one in all aspects, although it doesn’t seem to look much different.

Prices for the new one are realistic.

It seems better value than the old one, handles better and is much quieter, despite having a bigger engine – 999cc.

If you get chance, try one – you’ll either love it or hate it.

The current model is still doing well on the used car market, with a three-year old Pulse with 30,000 miles making £4,075 in clean condition, according to CAP Black Book.

Flew to Dublin to drive yet another four-wheel drive vehicle, this time from Volvo.

The all-new XC70 4WD and the V70, 113mm longer than the current models, were there for us to test.

Both cars have used the S80 as a starting point, with much of the front end the same.

The new cars certainly have better exterior styling, and the interiors now have a look and feel of quality.

We drove both cars on a variety of roads, and the XC70 on an off-road course normally used by Land Rovers, so it was quite steep and muddy. The XC70 proved a true off-roader.

Volvo told us that it invented the estate car back in 1953 with the launch of the Volvo Duette.

Did they invent the estate car? I’m not so sure but the estate is certainly what Volvo is good at, and it just gets better at doing it.

The XC70 and V70 are due in showrooms in September.