Vehicle buzzed in California desert by UFO in 1971

This is a sighting that i experienced over 30 years ago in the California desert.  I was returning from a trip to the Colorado River with my boyfriend. It was very late at night, as we waited until it was cooler, to avoid driving during the daytime heat.  We had left Parker on the Calif/Arizona border and were on Hwy 62 going toward Desert Center and I-10. It was midweek and late at night, so there was no traffic at all and very dark night.
Coming toward us over the road and from above, came a very fast large white light that swooped down at our car and then straight back up.  It was moving so fast it trailed light as it went. It made no sound and it arched sharply as it went back up as it approached the car.  We both leaned forward over the dash to try to see it as it went up.  It happened so quickly, but we stopped the car immediately and got out. We could see quite a distance around us, but it was already gone in a matter of seconds.  Over the years, I did the usual guessing "it must have been a top secret government plane, etc"  But as a reasonable person today, I know for a fact that there is nothing today that could move like that, and certainly nothing that many years ago.  I am convinced that the UFO spotted a single light moving in what must have been a vast amount of ground darkness and came down and buzzed us to see what we were.
Witness indicates that the date of the incident is approximate.  PD