Metropolitan Police officers were sent to 166 key junctions during rush-hour periods as part of Operation Safeway.
The operation, started in November, was due to end on 3 January but officers have extended it until the end of this week.
Det Ch Supt Glyn Jones said road users were behaving in a "much safer manner".
The operation followed the deaths of six cyclists in a two-week period in November.
Officers said the public's response to the operation had so far been "encouraging".
"We've noticed that road users are generally behaving in a much safer manner, and we have issued fewer fixed penalty notices as the operation has progressed," said Det Ch Supt Jones.
"This week, officers will be out again at key junctions, advising road users and enforcing the law where necessary. We want 2014 to be a safe year for all road users."
Since the beginning of Operation Safeway on 25 November, a total of 13,818 fines have been issued, with 4,085 given to cyclists.
Police said cyclists were fined for jumping red lights, cycling on footpaths and having incorrect lights.
Motorists were given fines for offences including driving without insurance and driving without wearing a seatbelt.
In addition 209 people were arrested during the operation for offences including assault, dangerous driving, driving while disqualified and drink driving.
More than 13,800 fines have been issued to drivers and cyclists during an operation in London sparked by the death of six cyclists in two weeks.