Fatal
Serious
Slight
Uncategorised
| Date | Local Authority | Vehicles | Casualties | Severity |
|---|---|---|---|---|
| Wed 1 Jan 1986 | Harrow | 1 | 1 | Slight |
| Mon 13 Jan 1986 | Three Rivers | 3 | 1 | Slight |
| Mon 13 Jan 1986 | Hertsmere | 2 | 1 | Slight |
| Tue 14 Jan 1986 | Hertsmere | 5 | 3 | Slight |
| Fri 17 Jan 1986 | Three Rivers | 1 | 1 | Slight |
| Sat 18 Jan 1986 | Hertsmere | 2 | 1 | Slight |
| Fri 24 Jan 1986 | Watford | 3 | 3 | Serious |
| Tue 28 Jan 1986 | Harrow | 2 | 1 | Slight |
| Wed 29 Jan 1986 | Hertsmere | 2 | 1 | Serious |
| Wed 5 Feb 1986 | Hertsmere | 3 | 1 | Slight |
| Wed 12 Feb 1986 | Watford | 2 | 1 | Slight |
| Sun 16 Feb 1986 | Watford | 2 | 1 | Slight |
| Wed 19 Feb 1986 | Hertsmere | 2 | 1 | Slight |
| Thu 20 Feb 1986 | Hertsmere | 2 | 1 | Serious |
| Sat 22 Feb 1986 | Watford | 1 | 1 | Serious |
| Sun 23 Feb 1986 | Hertsmere | 2 | 1 | Slight |
| Wed 26 Feb 1986 | Hertsmere | 2 | 1 | Serious |
| Tue 11 Mar 1986 | Hertsmere | 2 | 1 | Slight |
| Mon 17 Mar 1986 | Hertsmere | 2 | 1 | Slight |
| Sat 22 Mar 1986 | Harrow | 2 | 1 | Serious |
| Sat 22 Mar 1986 | Harrow | 2 | 1 | Serious |
| Sat 5 Apr 1986 | Hertsmere | 2 | 1 | Slight |
| Fri 25 Apr 1986 | Hertsmere | 2 | 1 | Slight |
| Sun 11 May 1986 | Three Rivers | 3 | 2 | Serious |
| Fri 16 May 1986 | Hertsmere | 2 | 1 | Serious |
| Sat 31 May 1986 | Three Rivers | 1 | 1 | Slight |
| Sun 8 Jun 1986 | Watford | 1 | 1 | Slight |
| Tue 10 Jun 1986 | Watford | 2 | 1 | Serious |
| Tue 15 Jul 1986 | Harrow | 3 | 1 | Slight |
| Tue 15 Jul 1986 | Harrow | 3 | 1 | Slight |
| Tue 29 Jul 1986 | Hertsmere | 1 | 1 | Serious |
| Fri 8 Aug 1986 | Harrow | 1 | 1 | Fatal |
| Tue 26 Aug 1986 | Hertsmere | 2 | 1 | Slight |
| Wed 17 Sep 1986 | Hertsmere | 2 | 1 | Slight |
| Thu 25 Sep 1986 | Hertsmere | 2 | 1 | Slight |
| Wed 1 Oct 1986 | Hertsmere | 1 | 1 | Serious |
| Tue 14 Oct 1986 | Watford | 2 | 2 | Slight |
| Tue 21 Oct 1986 | Watford | 2 | 2 | Serious |
| Thu 23 Oct 1986 | Hertsmere | 2 | 1 | Slight |
| Sat 25 Oct 1986 | Watford | 2 | 2 | Slight |
| Wed 12 Nov 1986 | Hertsmere | 1 | 1 | Slight |
| Fri 14 Nov 1986 | Harrow | 2 | 1 | Slight |
| Mon 8 Dec 1986 | Harrow | 4 | 1 | Slight |
| Wed 10 Dec 1986 | Three Rivers | 2 | 1 | Slight |
| Tue 16 Dec 1986 | Three Rivers | 3 | 1 | Slight |
| Fri 19 Dec 1986 | Hertsmere | 1 | 1 | Serious |