Fatal
Serious
Slight
Uncategorised
| Date | Local Authority | Vehicles | Casualties | Severity |
|---|---|---|---|---|
| Fri 1 Jan 1999 | Watford | 1 | 1 | Slight |
| Fri 15 Jan 1999 | Three Rivers | 2 | 2 | Serious |
| Mon 18 Jan 1999 | Watford | 2 | 1 | Slight |
| Fri 12 Feb 1999 | Three Rivers | 2 | 1 | Slight |
| Fri 19 Feb 1999 | Watford | 2 | 1 | Slight |
| Thu 25 Feb 1999 | Watford | 2 | 1 | Slight |
| Mon 15 Mar 1999 | Watford | 1 | 1 | Slight |
| Mon 15 Mar 1999 | Watford | 2 | 2 | Slight |
| Fri 19 Mar 1999 | Watford | 2 | 1 | Slight |
| Wed 5 May 1999 | Three Rivers | 2 | 2 | Slight |
| Fri 14 May 1999 | Three Rivers | 2 | 1 | Slight |
| Wed 19 May 1999 | Watford | 1 | 1 | Slight |
| Wed 9 Jun 1999 | Watford | 1 | 1 | Slight |
| Sat 12 Jun 1999 | Watford | 1 | 1 | Slight |
| Tue 15 Jun 1999 | Watford | 3 | 1 | Slight |
| Tue 29 Jun 1999 | Watford | 2 | 1 | Slight |
| Wed 21 Jul 1999 | Watford | 2 | 2 | Slight |
| Mon 2 Aug 1999 | Watford | 2 | 1 | Slight |
| Fri 13 Aug 1999 | Watford | 1 | 1 | Slight |
| Mon 13 Sep 1999 | Watford | 3 | 1 | Slight |
| Tue 21 Sep 1999 | Three Rivers | 1 | 1 | Serious |
| Wed 22 Sep 1999 | Three Rivers | 3 | 3 | Serious |
| Thu 30 Sep 1999 | Watford | 2 | 1 | Slight |
| Sat 9 Oct 1999 | Watford | 5 | 1 | Slight |
| Mon 11 Oct 1999 | Watford | 2 | 1 | Slight |
| Sun 17 Oct 1999 | Watford | 2 | 1 | Slight |
| Tue 19 Oct 1999 | Watford | 2 | 1 | Slight |
| Mon 25 Oct 1999 | Watford | 3 | 1 | Slight |
| Sun 7 Nov 1999 | Watford | 2 | 1 | Slight |
| Tue 16 Nov 1999 | Watford | 2 | 1 | Slight |
| Wed 15 Dec 1999 | Three Rivers | 2 | 1 | Slight |