Since this was filmed in England during World War II, the odd-looking things on most cars' headlights are blackout deflectors. These kept the light pointed down at the road ahead and much less visible to enemy planes from above.
This is one of about three dozen British films picked up by CBS in 1949 for USA television presentation; its initial telecasts took place in both New York City and in Baltimore Sunday 20 March 1949 on WCBS (Channel 2) and on WMAR (Channel 2).