The Road Speed was a car made by Marlborough between 1921 and 1923.

The car was fitted with a four-cylinder 1327cc side-valve engine. The engine was linked to a four-speed gearbox via a multi-plate clutch. The engine produced 20bhp and the car had a top speed of 70mph (113kmh). Later models were fitted with a 1496cc Anzani engine.

The Road Speed inherited it's 9ft chassis from the 10/16hp. This meant it had semi-elliptical leaf-springs at the front and three-quarter elliptical springs at the rear.

The car was fitted with two-seater body with an outside exhaust. The body had a tapering tail to which the spare wheel was fitted.

The car cost £690 when new. It is not known how many were made.