They may feature spikes, grooves, or caps to capture dirt and water, and be made from the synthetic rubber (often referred to as "vinyl" or "thermoplastic") or textile materials.
A more common method of retention, though, is a fitting system that hooks, clips, or twists into an anchor point already positioned on the vehicle floor.
Original equipment manufacturers are now starting to develop non-OEM channels to offer reduced cost vehicle mats and to expand their markets.
The NHTSA stated that the recall was due to the risk that unsecured mats could move forward and trap the gas pedal.
[1] On August 28, 2009, a two-car collision killed four people riding in a Lexus dealer-provided loaner ES 350 in San Diego, California; the accident was caused by the Lexus' incorrectly having been fitted with all-weather rubber floor mats meant for the RX 400h SUV, and the fact that these mats were not secured by either of the two retaining clips.
[2] The investigators' report stated that the accelerator pedal's hinge did not allow relieving of obstructions, and the dashboard lacked directions for the three-second emergency press of the push button keyless ignition.