There are many applications of heads up displays in the real world. Every vehicle will have some form of dashboard that displays all of the useful information to the driver; Fuel level, speed, and many different warnings about the state of the vehicle.
The fuel level is indicated by the fuel gauge, this is a curved display that shows the letter F at the top and E at the bottom, the F stands for ‘Full’ and the E stands for ‘Empty’.There are several dashes in between that show the level of fuel left in the car, an arrow points to the appropriate section of the display so that the driver knows how much fuel they have left.
The speed of the vehicle is measured with a Speedometer, this tells the driver how many miles per hour they are traveling (MPH are only used in the UK and the US, apart from a few countries the rest of the world used Kilometers per hour ‘KPH’, however many cars will display both to enable safe driving for people wishing to bring their car to another country). The gauge for a speedometer is shaped like a circle with a small segment missing at the bottom, the lowest speed appears on the left hand side of the gauge and the maximum speed appears on the right. There is an arm in the bottom-center of the gauge that points to the current traveling speed.
Warnings are given to the driver in the form of small light up icons, if there is a problem with the car ,for example low battery or faulty airbag, then a light will appear on the corresponding icon, this is usually accompanied by a dinging noise to alert the driver.
This is another real life example of a HUD, this is a little more extreme as the HUD has to be very clear to the pilot meaning that stylish designs are not welcome. Pilots will have an array of of meters and gauges telling them about various things throughout the cockpit but the most interesting feature is this lens that the pilot looks through so that they can see things such as the angle the plane is positioned in, the current flight path and airspeed.