Beam Patterns

Beam patterns are general descriptors for the spread and intensity of light.

The naming of beam patterns may be regulated and functional (like a low beam, high beam, or reverse light) which must shine light in specific way.

Off-road and non-regulated beam patterns are named in a subjective fashion. Every manufacturer has different ideas for what a "spot" or "driving" pattern should look like.

Common Non-Regulated Beam Patterns:

Flood type patterns are best for static (non-moving) use, or to fill an area at very low speed, like reverse lights.

• Flood generally means that there is a very wide spread of light. Since light shines everywhere, it's not a good choice above the hood, because it will cause glare off the hood.
• Scene is even larger than flood. Optic is usually totally removed, and this should not be used in motion.

Spot type patterns are best for high-speed driving, or search-and-rescue (like a flashlight). It's not a good choice for most casual off-road drivers.

• Spot is a highly concentrated beam of light. This is usually not useful for most drivers, but it's good for serious competitors who need long-range vision at high speed.
• Racer or Hyper Spot is an even tighter focused beam (however, Diode Spot is already very tight)

Driving type patterns are seen as the best all-around for general driving use (hence the name), and this is normally the pattern that should be recommended for forward-facing lights. But they vary quite a bit by manufacturer.

• SAE Driving is a regulated beam pattern. This is usually is the most useful for most off-road driving, because it is still concentrated for down-road vision, but has more spread than a simple spot light.
• Many Driving patterns are simply wider spot lights, sometimes called Broad Spot. But they become very unfocused, and almost look like a Combo. Baja Designs calls theirs a "Driving Combo" for example.
• Sometimes Driving is simply a tighter pattern than flood.

Combo is a light that shines with some intensity, but also fills the area.  It is seen as the “most versatile” option by most consumers, but they usually aren't very focused, making them best for use at lower speeds.

• Traditionally, this is a combination of Spot and Flood, but it could really be a combination of anything. 
• Wide (or Cornering) is a broad spread of light that isn’t as tall, but acts like a Combo. It can be used at lower speeds as a "fill" light, without shining everywhere like a Flood would, and has more intensity than a Flood.

SAE Fog is a specific pattern that is design to be very wide, and narrow. It should be mounted low so that the light can shine "under" the fog, and not up into the line of sight of the driver. 

Some examples: