Motor vehicle manufacturers each tend to have specific ideas about the best ways to light their vehicles and unfortunately this means that some of the more obscure bulbs can be maker or even model specific, but there is a certain amount of standardisation regarding the main automotive bulbs. As always, it is essential to ensure that the correctly rated bulb is fitted. Although LED bulbs have made some headway into this market, especially for use as daylight-running lights, the rugged simplicity of filament bulbs still makes them the first choice as car bulbs for indicators and rear/brake lights. Halogen bulbs are now standard for headlights. Any changes from the original vehicle specification need careful consideration and although some bulbs may offer improved brightness, many also change the light 'temperature', often resulting in a more blue-white for headlights, which may or may not be required or desired. Some vehicles employ Xenon bulbs requiring a much higher voltage and these are not interchangeable with other types. Standard car bulbs are of course 12V and most commercial vehicles employ a 24V electrical system.