Driving with lights on during day (DRL)
In some countries like Scandinavia it has been a rule for many years and now is every-day-life to drive with lights on even during day. What thereby is most important is not "to see well" but "to be seen well". There are many arguments that strongly support driving during day with lights on:

Daytime Running Light can contribute to...
...reduce the number of accidents as other road users are seen earlier even in bad weather and traffic conditions
...realize following road users earlier in the rear mirror and being able to adapt the own braking reactions according to minimize rear-end collisions
...pedestrians and cyclists better realizing approaching vehicles
...intensify reduced contrasts of the background that would hinder the view, like with clouds, sun reflexes, in areas with forests or trees.

There are studies that estimate the potential of rescuing human lives from a percentage of about 3 to 5 of the yearly serious car accidents.

To keep fuel consumption and CO2 emission on a relatively low level, there are special daytime running lamps, for example ini BMW 3series Cabrio/Coupé or Audi A4. Both headlamps clearly point out the opportunity to create an extraordinary styling with new technologies. (please see the pictures within the right column)

Legal requirements
In numerous countries there are already legal rules that regulate driving with light during day. They range from recommendations over restricted to complete obligation for driving with lights on.
The current status within different countries is shown in the following links:

European Rules American Rules

From 01/2011 onwards, all newly homologised vehicles have to be equipped with daytime running lamps.

Decision criteria for Daytime Running Light solutions
Special daytime running lamps can be realised with different solutions. These range from simple bulb technique to innovative LED-technology. When deciding for an alternative, subsequent factors play an important role:

- Styling and Design
- Lifetime
- Luminous flux
- Temperature load
- Costs

Advantages and disadvantages: Driving with low beam vs. Daytime Running Lamp
The requirement to drive with lights on during day can be realized with the conventional low beam turned on. Another alternative is to equip vehicles with special daytime running lamps. Both versions have advantages and disadvantages that are shown in the table below: