girl drives large car she is follow someone who has interest

[Ron Wolpa]

1970 early production
Young and beautiful lady drives a large 1970s model ...?..... it seems there is something of interest on behalf someone who follows her all the time as she drives down to a seashore place.
My memory tricks me because I thought the actress was Stephanie Powers.
I turned her filmography upside down to find no movie alike.
The same for Rachel Welch.
I know it is not so much to identify it but that´s all I can remember.

Thank you .

[Ag0stoMesmer]

Death Car on the Freeway?