Fatal
Serious
Slight
Uncategorised
| Date | Local Authority | Vehicles | Casualties | Severity |
|---|---|---|---|---|
| Sun 1 Jan 1989 | Hertsmere | 1 | 1 | Serious |
| Tue 3 Jan 1989 | Hertsmere | 2 | 1 | Slight |
| Tue 3 Jan 1989 | Hertsmere | 2 | 2 | Fatal |
| Thu 5 Jan 1989 | Hertsmere | 1 | 1 | Slight |
| Thu 12 Jan 1989 | Barnet | 1 | 1 | Serious |
| Thu 12 Jan 1989 | Barnet | 2 | 1 | Slight |
| Wed 18 Jan 1989 | Watford | 2 | 1 | Slight |
| Fri 20 Jan 1989 | Hertsmere | 3 | 1 | Slight |
| Thu 26 Jan 1989 | Barnet | 1 | 1 | Slight |
| Thu 26 Jan 1989 | Hertsmere | 2 | 1 | Serious |
| Sat 28 Jan 1989 | Hertsmere | 2 | 1 | Slight |
| Sun 29 Jan 1989 | Barnet | 1 | 1 | Slight |
| Sun 29 Jan 1989 | Barnet | 2 | 1 | Serious |
| Sat 4 Feb 1989 | Hertsmere | 2 | 1 | Slight |
| Sat 4 Feb 1989 | Watford | 2 | 1 | Serious |
| Tue 7 Feb 1989 | Watford | 1 | 1 | Slight |
| Thu 9 Feb 1989 | Hertsmere | 2 | 1 | Slight |
| Thu 9 Feb 1989 | Three Rivers | 2 | 1 | Slight |
| Sat 11 Feb 1989 | Barnet | 2 | 1 | Slight |
| Fri 17 Feb 1989 | Barnet | 2 | 1 | Slight |
| Sat 18 Feb 1989 | Watford | 2 | 1 | Slight |
| Sat 25 Feb 1989 | Barnet | 1 | 1 | Slight |
| Sat 25 Feb 1989 | Watford | 2 | 1 | Slight |
| Mon 27 Feb 1989 | Watford | 2 | 2 | Slight |
| Wed 1 Mar 1989 | Barnet | 2 | 1 | Slight |
| Thu 2 Mar 1989 | Watford | 1 | 1 | Slight |
| Sat 4 Mar 1989 | Watford | 4 | 2 | Slight |
| Sat 4 Mar 1989 | Barnet | 1 | 1 | Slight |
| Tue 7 Mar 1989 | Watford | 2 | 1 | Slight |
| Tue 7 Mar 1989 | Hertsmere | 2 | 1 | Slight |
| Sun 12 Mar 1989 | Barnet | 2 | 1 | Slight |
| Mon 13 Mar 1989 | Barnet | 1 | 1 | Slight |
| Sun 19 Mar 1989 | Watford | 2 | 1 | Slight |
| Sun 19 Mar 1989 | Barnet | 2 | 1 | Slight |
| Wed 22 Mar 1989 | Hertsmere | 2 | 1 | Slight |
| Thu 23 Mar 1989 | Barnet | 1 | 1 | Slight |
| Wed 29 Mar 1989 | Watford | 2 | 1 | Slight |
| Sat 1 Apr 1989 | Watford | 2 | 6 | Slight |
| Sat 1 Apr 1989 | Hertsmere | 2 | 2 | Slight |
| Fri 7 Apr 1989 | Watford | 2 | 1 | Slight |
| Fri 7 Apr 1989 | Watford | 2 | 1 | Serious |
| Tue 18 Apr 1989 | Barnet | 1 | 1 | Slight |
| Wed 19 Apr 1989 | Barnet | 1 | 1 | Slight |
| Sun 23 Apr 1989 | Barnet | 2 | 1 | Slight |
| Sat 29 Apr 1989 | Watford | 3 | 2 | Slight |
| Tue 2 May 1989 | Barnet | 2 | 1 | Slight |
| Wed 3 May 1989 | Watford | 2 | 1 | Slight |
| Thu 4 May 1989 | Watford | 2 | 2 | Serious |
| Wed 10 May 1989 | Watford | 4 | 1 | Slight |
| Fri 12 May 1989 | Watford | 2 | 1 | Slight |
| Mon 15 May 1989 | Hertsmere | 2 | 1 | Slight |
| Tue 23 May 1989 | Watford | 2 | 1 | Slight |
| Thu 25 May 1989 | Watford | 1 | 1 | Slight |
| Tue 30 May 1989 | Hertsmere | 1 | 1 | Slight |
| Tue 30 May 1989 | Hertsmere | 2 | 1 | Slight |
| Tue 30 May 1989 | Three Rivers | 3 | 2 | Slight |
| Wed 31 May 1989 | Hertsmere | 2 | 2 | Slight |
| Fri 2 Jun 1989 | Watford | 2 | 1 | Slight |
| Tue 6 Jun 1989 | Watford | 2 | 1 | Slight |
| Thu 8 Jun 1989 | Watford | 2 | 1 | Slight |
| Thu 8 Jun 1989 | Barnet | 2 | 1 | Slight |
| Mon 12 Jun 1989 | Barnet | 2 | 1 | Slight |
| Thu 15 Jun 1989 | Barnet | 2 | 1 | Slight |
| Mon 19 Jun 1989 | Watford | 2 | 1 | Slight |
| Sat 24 Jun 1989 | Barnet | 2 | 2 | Slight |
| Mon 26 Jun 1989 | Watford | 2 | 1 | Slight |
| Thu 29 Jun 1989 | Hertsmere | 1 | 1 | Slight |
| Fri 30 Jun 1989 | Watford | 2 | 1 | Slight |
| Tue 4 Jul 1989 | Watford | 1 | 1 | Slight |
| Wed 5 Jul 1989 | Watford | 2 | 1 | Slight |
| Sun 9 Jul 1989 | Hertsmere | 1 | 1 | Slight |
| Tue 11 Jul 1989 | Barnet | 2 | 1 | Slight |
| Tue 11 Jul 1989 | Watford | 2 | 1 | Slight |
| Thu 13 Jul 1989 | Watford | 2 | 2 | Slight |
| Sun 16 Jul 1989 | Barnet | 2 | 1 | Slight |
| Wed 19 Jul 1989 | Watford | 2 | 1 | Slight |
| Wed 19 Jul 1989 | Hertsmere | 2 | 5 | Slight |
| Thu 20 Jul 1989 | Barnet | 2 | 1 | Slight |
| Thu 20 Jul 1989 | Watford | 2 | 1 | Slight |
| Thu 20 Jul 1989 | Barnet | 2 | 3 | Slight |
| Fri 21 Jul 1989 | Watford | 2 | 1 | Slight |
| Fri 21 Jul 1989 | Watford | 2 | 1 | Slight |
| Fri 28 Jul 1989 | Hertsmere | 1 | 1 | Slight |
| Fri 28 Jul 1989 | Watford | 1 | 1 | Serious |
| Fri 28 Jul 1989 | Watford | 1 | 1 | Serious |
| Tue 1 Aug 1989 | Watford | 1 | 1 | Slight |
| Sun 13 Aug 1989 | Watford | 2 | 1 | Slight |
| Sun 20 Aug 1989 | Watford | 2 | 1 | Slight |
| Wed 23 Aug 1989 | Barnet | 2 | 1 | Slight |
| Sat 2 Sep 1989 | Watford | 6 | 2 | Slight |
| Mon 4 Sep 1989 | Watford | 2 | 1 | Slight |
| Sun 10 Sep 1989 | Hertsmere | 2 | 2 | Serious |
| Tue 12 Sep 1989 | Barnet | 2 | 1 | Slight |
| Wed 13 Sep 1989 | Hertsmere | 2 | 1 | Slight |
| Thu 14 Sep 1989 | Watford | 2 | 1 | Slight |
| Sat 16 Sep 1989 | Barnet | 1 | 1 | Slight |
| Sun 17 Sep 1989 | Hertsmere | 3 | 1 | Slight |
| Tue 19 Sep 1989 | Barnet | 2 | 1 | Slight |
| Tue 19 Sep 1989 | Watford | 2 | 1 | Slight |
| Fri 22 Sep 1989 | Barnet | 2 | 1 | Slight |
| Sat 23 Sep 1989 | Watford | 2 | 1 | Serious |
| Mon 25 Sep 1989 | Barnet | 2 | 1 | Slight |
| Mon 2 Oct 1989 | Watford | 2 | 1 | Slight |
| Mon 9 Oct 1989 | Barnet | 2 | 2 | Slight |
| Fri 13 Oct 1989 | Watford | 1 | 1 | Slight |
| Tue 17 Oct 1989 | Barnet | 2 | 1 | Slight |
| Tue 17 Oct 1989 | Watford | 2 | 1 | Slight |
| Tue 17 Oct 1989 | Watford | 2 | 1 | Slight |
| Sat 21 Oct 1989 | Hertsmere | 1 | 1 | Slight |
| Mon 23 Oct 1989 | Watford | 2 | 1 | Serious |
| Wed 25 Oct 1989 | Watford | 2 | 1 | Slight |
| Thu 26 Oct 1989 | Hertsmere | 2 | 1 | Slight |
| Wed 1 Nov 1989 | Hertsmere | 2 | 1 | Serious |
| Thu 2 Nov 1989 | Watford | 2 | 1 | Slight |
| Fri 3 Nov 1989 | Hertsmere | 1 | 1 | Slight |
| Tue 7 Nov 1989 | Watford | 4 | 1 | Slight |
| Tue 7 Nov 1989 | Hertsmere | 2 | 1 | Slight |
| Thu 9 Nov 1989 | Hertsmere | 1 | 1 | Slight |
| Fri 10 Nov 1989 | Hertsmere | 2 | 1 | Slight |
| Fri 10 Nov 1989 | Watford | 2 | 2 | Slight |
| Fri 10 Nov 1989 | Barnet | 2 | 1 | Slight |
| Sat 11 Nov 1989 | Hertsmere | 1 | 1 | Slight |
| Sun 12 Nov 1989 | Hertsmere | 3 | 3 | Slight |
| Mon 13 Nov 1989 | Hertsmere | 1 | 1 | Slight |
| Thu 16 Nov 1989 | Watford | 2 | 2 | Slight |
| Fri 24 Nov 1989 | Barnet | 1 | 1 | Slight |
| Fri 24 Nov 1989 | Watford | 2 | 1 | Slight |
| Sat 25 Nov 1989 | Hertsmere | 2 | 4 | Serious |
| Mon 27 Nov 1989 | Watford | 2 | 2 | Slight |
| Tue 28 Nov 1989 | Watford | 1 | 1 | Slight |
| Fri 1 Dec 1989 | Barnet | 4 | 1 | Slight |
| Fri 1 Dec 1989 | Barnet | 1 | 1 | Serious |
| Fri 1 Dec 1989 | Barnet | 1 | 1 | Serious |
| Sat 2 Dec 1989 | Barnet | 2 | 2 | Slight |
| Sat 2 Dec 1989 | Watford | 2 | 2 | Slight |
| Tue 5 Dec 1989 | Barnet | 1 | 1 | Slight |
| Wed 6 Dec 1989 | Watford | 2 | 2 | Slight |
| Wed 6 Dec 1989 | Watford | 2 | 1 | Slight |
| Wed 6 Dec 1989 | Hertsmere | 2 | 1 | Slight |
| Sat 9 Dec 1989 | Watford | 2 | 1 | Slight |
| Wed 13 Dec 1989 | Barnet | 1 | 1 | Slight |
| Sat 16 Dec 1989 | Hertsmere | 3 | 1 | Slight |
| Sun 17 Dec 1989 | Watford | 1 | 1 | Slight |
| Mon 18 Dec 1989 | Watford | 2 | 1 | Slight |
| Thu 21 Dec 1989 | Barnet | 2 | 1 | Slight |
| Fri 22 Dec 1989 | Watford | 2 | 1 | Slight |
| Sat 23 Dec 1989 | Barnet | 3 | 2 | Slight |
| Sat 23 Dec 1989 | Watford | 2 | 1 | Slight |
| Tue 26 Dec 1989 | Barnet | 2 | 1 | Slight |
| Thu 28 Dec 1989 | Hertsmere | 2 | 4 | Serious |