We were on Hwy I-10 traveling from CA. to AZ. At approx 10 p.m. the speedometer in the car started jumping erratically from 0- 130 miles per hour. This was strange as my speedometer doesn't even wiggle in the slightest, ever! We jokingly said, 'the aliens must be overhead". Seriously I was worried that I was about to have car trouble in this very unpopulated, no services area. We call it no mans land between Indio CA. & the state line. The speedometer continued to act erratically for about 1/2 hour and as suddenly as it started it regained it's usual reliable behavior. We would never have thought much more about this except then we heard the reports of the light sightings over the Phoenix area that left the view of that vicinity around 10p.m. Anyway, just letting you know of a weird, coincidental occurrence.