The Minnesota Department of Transportation is making safety improvements and will convert more than 28,000 roadway lights which currently use high pressure sodium lights. 

Before we get into it, let's do some research and learn more about this conversion. According to a guide to converting to LED street lighting from LEOTEK the pros to LED lighting are:

  • Improve nighttime visibility and have better color rendering.
  • Reduce uplighting which cause 'urban sky glow'.
  • 40-80% energy savings depending on lighting design criteria.
  • 50-75% street lighting maintenance savings.

Now time for the negatives:

  • LED lights are usually twice the amount of conventional style lights if not more.
  • Because of the lack of standardized wattages and the complexities of getting new rates approved, most regulated Investor Owned Utilities today don’t offer LED street light tariffs for unmetered street lights.

Most cities use HPS (High Pressure Sodium) due to its longevity, efficiency, and small in size. However a lot of cities are now converting to LED. HPS lights have bad color rendering and operate on a low arc voltage which reduces efficiency all together.

MnDOT expects energy cost savings to be up to $1.45 million a year with an additional $500,000 per year savings in maintenance and replacement costs for light fixtures and bulbs. The entire conversion is expected to be completed by 2020. Let me know what you think of this conversion in the comments below.