Fatal
Serious
Slight
Uncategorised
| Date | Local Authority | Vehicles | Casualties | Severity |
|---|---|---|---|---|
| Wed 6 Jan 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Fri 8 Jan 1999 | Stevenage | 2 | 1 | Slight |
| Wed 27 Jan 1999 | Welwyn Hatfield | 2 | 1 | Serious |
| Thu 18 Feb 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Sat 27 Feb 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Tue 2 Mar 1999 | North Hertfordshire | 3 | 1 | Slight |
| Thu 18 Mar 1999 | North Hertfordshire | 2 | 1 | Slight |
| Sun 21 Mar 1999 | Welwyn Hatfield | 2 | 2 | Slight |
| Sat 27 Mar 1999 | Stevenage | 2 | 1 | Slight |
| Sun 11 Apr 1999 | Stevenage | 2 | 1 | Slight |
| Tue 13 Apr 1999 | North Hertfordshire | 3 | 1 | Slight |
| Tue 13 Apr 1999 | North Hertfordshire | 3 | 1 | Slight |
| Wed 14 Apr 1999 | Welwyn Hatfield | 3 | 3 | Serious |
| Thu 15 Apr 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Wed 21 Apr 1999 | Welwyn Hatfield | 1 | 1 | Slight |
| Mon 26 Apr 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Mon 26 Apr 1999 | Stevenage | 1 | 1 | Slight |
| Fri 30 Apr 1999 | North Hertfordshire | 2 | 1 | Slight |
| Wed 5 May 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Thu 13 May 1999 | Welwyn Hatfield | 1 | 1 | Slight |
| Wed 26 May 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Sat 29 May 1999 | Welwyn Hatfield | 1 | 1 | Slight |
| Tue 1 Jun 1999 | Welwyn Hatfield | 1 | 1 | Serious |
| Thu 3 Jun 1999 | Welwyn Hatfield | 4 | 1 | Slight |
| Tue 8 Jun 1999 | Stevenage | 2 | 1 | Slight |
| Tue 8 Jun 1999 | Welwyn Hatfield | 3 | 2 | Slight |
| Tue 29 Jun 1999 | Welwyn Hatfield | 2 | 2 | Slight |
| Wed 30 Jun 1999 | North Hertfordshire | 3 | 1 | Slight |
| Fri 9 Jul 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Wed 14 Jul 1999 | Welwyn Hatfield | 3 | 1 | Slight |
| Mon 26 Jul 1999 | Stevenage | 2 | 1 | Slight |
| Sun 1 Aug 1999 | North Hertfordshire | 3 | 2 | Slight |
| Wed 11 Aug 1999 | Welwyn Hatfield | 3 | 2 | Slight |
| Thu 12 Aug 1999 | Welwyn Hatfield | 3 | 1 | Slight |
| Tue 17 Aug 1999 | North Hertfordshire | 2 | 3 | Slight |
| Tue 31 Aug 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Sun 19 Sep 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Mon 20 Sep 1999 | North Hertfordshire | 2 | 1 | Slight |
| Mon 20 Sep 1999 | North Hertfordshire | 2 | 1 | Slight |
| Tue 28 Sep 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Tue 5 Oct 1999 | Welwyn Hatfield | 2 | 2 | Slight |
| Tue 12 Oct 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Thu 14 Oct 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Fri 22 Oct 1999 | Welwyn Hatfield | 1 | 1 | Slight |
| Sat 30 Oct 1999 | Welwyn Hatfield | 1 | 1 | Serious |
| Tue 2 Nov 1999 | Stevenage | 1 | 1 | Slight |
| Sun 7 Nov 1999 | North Hertfordshire | 3 | 3 | Slight |
| Mon 8 Nov 1999 | North Hertfordshire | 1 | 1 | Slight |
| Thu 11 Nov 1999 | Stevenage | 2 | 1 | Slight |
| Tue 16 Nov 1999 | Welwyn Hatfield | 2 | 5 | Slight |
| Fri 19 Nov 1999 | Stevenage | 2 | 1 | Slight |
| Sat 20 Nov 1999 | Welwyn Hatfield | 2 | 2 | Slight |
| Thu 2 Dec 1999 | North Hertfordshire | 2 | 1 | Slight |
| Fri 3 Dec 1999 | Welwyn Hatfield | 2 | 2 | Slight |
| Tue 7 Dec 1999 | North Hertfordshire | 1 | 2 | Serious |
| Thu 9 Dec 1999 | Welwyn Hatfield | 2 | 2 | Slight |
| Fri 10 Dec 1999 | Welwyn Hatfield | 2 | 1 | Slight |
| Fri 10 Dec 1999 | Stevenage | 1 | 1 | Slight |
| Mon 13 Dec 1999 | Stevenage | 2 | 1 | Serious |