Offroad vehicles like ATVs and trailbikes use knobbly tyres to provide grip on uneven surfaces.
The downside of this is that, when these tyres hit tarmac, they have a dangerous tendency to suddenly adhere to the surface and flip the vehicle over unpredictably (more than 300 people died in on-road ATV accidents in 2011).
Today’s invention is a set of clip-on rubber covers for knobbly tyres (shown here in translucent red). These have smooth exterior and an interior surface that loosely fits the pattern of knobs, so that they stay in place when the driver/rider encounters tarmac and thus they allow short, slow journeys to be made in safety.
This has the additional benefit of improved fuel economy when being driven on-road.