"Beep and creep” traffic (or “creep and beep” traffic) is an expression for when traffic slows down, cars creep along, and traffic horns start to beep. Both “beep” and creep” (cited in print February 1969) and “creep and beep” (cited in print May 1969) are first cited from Boston, Massachusetts.
Another term for “beep and creep” is “crawl and stall.”
16 February 1969, Boston (MA) Globe, “Planning Beats Plowing” by Stephen Kurkjian, pg. 24:
A week after the storm, ruts in the roads and streets in Boston make traveling a beep and creep venture.
21 May 1969, Boston (MA) Herald Traveler, “At Last, It’s Open!,” pg. 3, col. 1:
The result was less “creep and beep” traffic, less exasperation and an earlier arrival at the supper table.
6 June 1969, Boston (MA) Herald Traveler, “Action Line” edited by Joe McLaughlin, pg. 48, col. 4:
Law abiding drivers beep and creep southward in the two travel lanes in utter frustration while lawless renegades careen down the breakdown lane.
R.N., Nashua, N.H.
24 July 1970, Record American (Boston, MA), “3-Month X-Way Repair to Slow All Road Traffic,” pg. 66, col. 2:
The Southeast Expressway’s creep and beep traffic is scheduled to become even creepier starting Monday.
2 December 1973, Boston (MA) Globe, “Lampoon awards go to Lovelace “ by Paul Kneeland, pg. 14:
The crowd that filled the streets—auto traffic was creep and beep—roared.
Google News Archive
8 April 1978, The Free Lance-Star (Fredericksburg, VA), For Solitude, There’s No Place Like A Car” by Ellen Goodman, pg. 8, col. 4:
There is, after all, nothing especially convenient about wending through the “creep and beep,” “stall and crawl” rush hour on city streets.
I Stand Corrected:
More On Language
By William Safire
New York, NY: Avon
So the traffic flow may be described as “beep and creep,” “bump and grump,” or “stall and crawl.”
By Darrel Montero and Judith McDowell
New York, NY: Macmillan; London: Collier Macmillan
There is, after all, nothing especially convenient about wending through the “creep and beep,” “stall and crawl” rush hour on city streets
11 March 1987, Newsday (Long Island, NY), “Signposts,” pg. 45:
Something to dream about when you’re stuck in Midtown gridlock or LIE beep- and-creep,
28 December 2007, Christian Science Monitor, “What our lawyers won’t let us say” by Ruth Walker:
And what did I get to watch during the beep-and-creep through Midtown from Penn Station to my hotel?