Segway Inc. has issued a voluntary recall of about 23,500 personal transporters due to a software glitch.

The transporters' wheels can unexpectedly reverse direction, causing riders to fall, the U.S. Consumer Product Safety Commission said in an advisory. Consumers are advised to stop using the Segway transporters immediately and contact the company for a free software upgrade.

The U.S.-based company has received six reports of Segway transporters malfunctioning, resulting in injuries to the head and wrists of users.

The recall involves all Segway PT i167, i170 and i180 models, the p133 series, the XT cross-terrain transporter, the golf transporter and i2 models. The e167 models are also are included in this recall.

The high-tech scooters were sold from March 2002 through mid-September 2006.

Company website

Recall notice