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