It’s scarily easy to find yourself driving too fast or losing concentration when a favourite song or an absorbing conversation starts up on the radio.

Today’s invention is a car radio which records an identifier of every programme item which is played and when -whether that be a talk show or a particular track on an album.

It does this in order to gather data about what, if anything, was playing at the reported time when an accident occurred.

The statistics generated from an entire population of drivers would show up any patterns in what specific sounds and types of sounds, at different times of the day and locations, were most likely to have been playing, just pre-RTA.

If you insist on listening to heavy metal at top volume at 3am, you might find a message appearing on your in-car entertainment system alerting you to the increased cost of your insurance for that trip.

It’s common to find that one’s DVD has a commentary on the film made by the cast, Director etc.

Today’s invention is an upgrade of that process for complex movies and on behalf of those of us who sometimes struggle to understand nuances in the plot.

The movie would be shown on a touchscreen, so that a viewer could click on a particular character and have a thought bubble appear.

This would state, without plot spoilers, who the person was, what they were currently doing and why.

This would also allow the Directors of films to indulge in very complex storytelling, without having to dumb-down their vision because they suspected that it would be just too hard to follow.

Today’s invention is based on the idea that there is a difference between the accelerative and constant velocity regimes of vehicle movement.

We tend to rely on tyred wheels for both -which entails a compromise between maximising drive and minimising rolling resistance.

Instead, imagine a vehicle with a fat, high-grip drive band (yellow) to be used only during acceleration or deceleration, together with very thin-tyred, slim wheels (blue) to be used only when the vehicle is moving along at top speed on a smooth surface.

These two elements would be swapped in or out depending on the position of the accelerator pedal.

According to my back-of-the-envelope calculation, the flow velocity within an exhaust pipe of a standard sized car is a small fraction of the speed of sound in carbon dioxide.

This allows me to treat the exhaust pipe, for acoustic purposes, as if it were filled with static fluid.

Today’s invention is therefore a suppressor for combustion engine exhaust noise.

Each pulsewave emitted by the opening or closing of the exhaust valve is allowed to pass into the clockwise arm of the looped pipe at 1 o’clock * (using a valve linked to the exhaust valve itself -not shown).

Once the pulse travels around the loop, it is allowed to leave using another linked valve at the 11 o’clock position.

By tuning the length of the loop to be (n+ 1/2)*the exhaust note wavelength, destructive interference can occur between the exhaust and loop waves, greatly reducing the engine noise emitted.

*I had to rethink this whole thing to avoid using the valves and fixed-length loop (thanks Andy, see below). Instead, a toroidal loop would be inserted in the exhaust as shown. A port would allow waves to enter and propagate around the loop. The loop itself would be spun, much faster than the wave speed, so as to position its port against the exhaust pipe. It would do this in such a way that if a compression were moving down the exhaust, the loop would inject a rarifaction and vice versa. In this way, pressure fluctuations could be eliminated within the exhaust, without introducing extra ones by the operation of conventional valves.