The total number of cars on UK roads has grown by 9% over the last 10 years, but that is a slower rate than the previous decade which saw a 17% rise, according to new figures released by the Society of Motor Manufacturers and Traders (SMMT).

The recession has changed the shape of the UK’s car parc. To the end of last year, the total parc increased to 31,362,716, up on 2010 by 104,519 units (0.3%). The average car on UK roads is now 7.44 years old, around two months older than a year ago, suggesting cash strapped motorists are keeping cars for longer.

However, this could be a false economy as the average new car is 20% more efficient than a typical seven year old car, saving the average motorist around £400 each year.

In the average car’s lifetime, it will have four owners, but there are 341 cars on UK roads with more than 20 registered keepers, and more than 5.3 million cars over 12 years old.

The data comes from the SMMT’s largest ever annual Motorparc census that analyses full details including make, model, variant, colour, emissions and age of every car, van, truck, bus and coach on UK roads.

Fuel efficiency

Motorists continued to seek out the most fuel efficient vehicles in 2011, as diesel car registrations overtook petrol for the first time taking a 50.6% market share. The growing trend of diesel registrations, coupled with the increasing share of alternatively-fuelled vehicles, resulted in there now being fewer petrol cars on the road than at any time since 1988.

With fuel efficiency at the front of every motorist’s mind, it is no surprise to see the number of tax-free cars on the road double since last year to more than 120,000 vehicles (cars emitting under 100g/km CO2 pay £0 VED).

Top five most popular cars on UK roads

1. Ford Focus
2. Ford Fiesta
3. Vauxhall Astra
4. Vauxhall Corsa
5. Volkswagen Golf

Main growth segments over last decade

MPV 205%
Dual purpose / 4x4 124%
Mini 43%
Supermini 34%
Specialist Sports 27%

Choice of colour

In the race for gold, silver and bronze, Wales tops the podium boasting the largest proportion of gold cars. Silver is the UK’s number one colour, but the North West has the biggest share, while the roads of the West Midlands have the greatest proportion of bronze cars.

Why Wight is red
The Isle of Wight is the most popular place in the UK for red cars, but the colour’s popularity has tumbled since peaking in 1999 when 25% (6.7 million) of all cars across the country were red. Today, just 12% of motorists favour the colour with Londoners leading the trend away from red, representing just 9% of the city’s cars.