A fleet tracking firm claims that a company's wisest investment for its fleet are GPS units which can save thousands in fuel costs.

Rocky Mountain Tracking said that its NavIQ GPS tracker software allows companies to monitor various aspects of a vehicle's performance, including speed and petrol consumption.

Every mile per hour increase above the optimum vehicle speed of 50mph results in increased fuel consumption of 1.5 per cent, while half an hour of idle time uses an entire gallon of petrol.

"When oil is hitting $140 a barrel and people are predicting prices as high as $200, it can be comforting to know that your vehicles are saving every drop of fuel possible," said Brad Borst, president of Rocky Mountain Tracking.

"With numerous GPS tracking features, you can look forward to thousands of dollars in fuel savings every month."

Borst said that companies can also ensure that vehicles are taking the shortest route between two points.

In addition, companies with employee take-home vehicles can cut down on unauthorised use as NavIQ generates graphs and reports of dates, times and locations of all vehicles.

"For an average fleet of 10 vehicles, companies are saving as much as $8,000 per month with GPS tracking devices," said Borst.

"Every dollar counts in today's economy, and fuel savings can give your company a genuine edge over the competition."