An orb of orange/yellow light that pulsated or dimmed then brightened period of about a second

Driving to work at about 4:30am on 4/27/99 I noticed a strange light quite a distance ahead of me.  At first I thought it was commercial aircraft, but I soon realized that it was not because it was a single orb of orange/yellow light that pulsated and remained stationary.  I knew it wasn't a copter because copters have more than one light and they don't pulsate. I continued looking at this thing and soon approached it, but it still did not move and continued to pulsate.  This event probably occurred in about 5 minutes time since I was traveling at about 40 mph. I continued to look back after I passed it, and it continued its strange behavior.